refactor(compiler): generate less code for bindings to DOM elements

Detailed changes:
- remove `UNINITIALIZED`, initialize change detection fields with `undefined`.
  * we use `view.numberOfChecks === 0` now everywhere
    as indicator whether we are in the first change detection cycle
    (previously we used this only in a couple of places).
  * we keep the initialization itself as change detection get slower without it.
- remove passing around `throwOnChange` in various generated calls,
  and store it on the view as property instead.
- change generated code for bindings to DOM elements as follows:
  Before:
  ```
  var currVal_10 = self.context.bgColor;
  if (jit_checkBinding15(self.throwOnChange,self._expr_10,currVal_10)) {
    self.renderer.setElementStyle(self._el_0,'backgroundColor',((self.viewUtils.sanitizer.sanitize(jit_21,currVal_10) == null)? null: self.viewUtils.sanitizer.sanitize(jit_21,currVal_10).toString()));
    self._expr_10 = currVal_10;
  }
  var currVal_11 = jit_inlineInterpolate16(1,' ',self.context.data.value,' ');
  if (jit_checkBinding15(self.throwOnChange,self._expr_11,currVal_11)) {
    self.renderer.setText(self._text_1,currVal_11);
    self._expr_11 = currVal_11;
  }
  ```,
  After:
  ```
  var currVal_10 = self.context.bgColor;
  jit_checkRenderStyle14(self,self._el_0,'backgroundColor',null,self._expr_10,self._expr_10=currVal_10,false,jit_21);
  var currVal_11 = jit_inlineInterpolate15(1,' ',self.context.data.value,' ');
  jit_checkRenderText16(self,self._text_1,self._expr_11,self._expr_11=currVal_11,false);
  ```

Performance impact:
- None seen (checked against internal latency lab)

Part of #13651

modules/@angular/upgrade/src/aot/downgrade_component_adapter.ts

@@ -62,8 +62,9 @@ export class DowngradeComponentAdapter {
           return (value: any /** TODO #9100 */) => {
             if (this.inputChanges !== null) {
               this.inputChangeCount++;
-              this.inputChanges[prop] =
-                  new Ng1Change(value, prevValue === INITIAL_VALUE ? value : prevValue);
+              this.inputChanges[prop] = new SimpleChange(
+                  value, prevValue === INITIAL_VALUE ? value : prevValue,
+                  prevValue === INITIAL_VALUE);
               prevValue = value;
             }
             this.component[prop] = value;
@@ -82,14 +83,14 @@ export class DowngradeComponentAdapter {
       }
       if (expr != null) {
         const watchFn =
-            ((prop: any /** TODO #9100 */) =>
-                 (value: any /** TODO #9100 */, prevValue: any /** TODO #9100 */) => {
-                   if (this.inputChanges != null) {
-                     this.inputChangeCount++;
-                     this.inputChanges[prop] = new Ng1Change(prevValue, value);
-                   }
-                   this.component[prop] = value;
-                 })(input.prop);
+            ((prop: any /** TODO #9100 */) => (
+                 value: any /** TODO #9100 */, prevValue: any /** TODO #9100 */) => {
+              if (this.inputChanges != null) {
+                this.inputChangeCount++;
+                this.inputChanges[prop] = new SimpleChange(prevValue, value, prevValue === value);
+              }
+              this.component[prop] = value;
+            })(input.prop);
         this.componentScope.$watch(expr, watchFn);
       }
     }
@@ -172,9 +173,3 @@ export class DowngradeComponentAdapter {
     });
   }
 }
-
-class Ng1Change implements SimpleChange {
-  constructor(public previousValue: any, public currentValue: any) {}
-
-  isFirstChange(): boolean { return this.previousValue === this.currentValue; }
-}

modules/@angular/upgrade/src/downgrade_ng2_adapter.ts

@@ -54,8 +54,9 @@ export class DowngradeNg2ComponentAdapter {
           return (value: any /** TODO #9100 */) => {
             if (this.inputChanges !== null) {
               this.inputChangeCount++;
-              this.inputChanges[prop] =
-                  new Ng1Change(value, prevValue === INITIAL_VALUE ? value : prevValue);
+              this.inputChanges[prop] = new SimpleChange(
+                  value, prevValue === INITIAL_VALUE ? value : prevValue,
+                  prevValue === INITIAL_VALUE);
               prevValue = value;
             }
             this.component[prop] = value;
@@ -73,14 +74,14 @@ export class DowngradeNg2ComponentAdapter {
       }
       if (expr != null) {
         const watchFn =
-            ((prop: any /** TODO #9100 */) =>
-                 (value: any /** TODO #9100 */, prevValue: any /** TODO #9100 */) => {
-                   if (this.inputChanges != null) {
-                     this.inputChangeCount++;
-                     this.inputChanges[prop] = new Ng1Change(prevValue, value);
-                   }
-                   this.component[prop] = value;
-                 })(input.prop);
+            ((prop: any /** TODO #9100 */) => (
+                 value: any /** TODO #9100 */, prevValue: any /** TODO #9100 */) => {
+              if (this.inputChanges != null) {
+                this.inputChangeCount++;
+                this.inputChanges[prop] = new SimpleChange(prevValue, value, prevValue === value);
+              }
+              this.component[prop] = value;
+            })(input.prop);
         this.componentScope.$watch(expr, watchFn);
       }
     }
@@ -152,9 +153,3 @@ export class DowngradeNg2ComponentAdapter {
     });
   }
 }
-
-class Ng1Change implements SimpleChange {
-  constructor(public previousValue: any, public currentValue: any) {}
-
-  isFirstChange(): boolean { return this.previousValue === this.currentValue; }
-}