fix(core): require 'static' flag on queries in typings (#30639)

This commit makes the static flag on @ViewChild and @ContentChild required.

BREAKING CHANGE:

In Angular version 8, it's required that all @ViewChild and @ContentChild
queries have a 'static' flag specifying whether the query is 'static' or
'dynamic'. The compiler previously sorted queries automatically, but in
8.0 developers are required to explicitly specify which behavior is wanted.
This is a temporary requirement as part of a migration; see
https://angular.io/guide/static-query-migration for more details.

@ViewChildren and @ContentChildren queries are always dynamic, and so are
unaffected.

PR Close #30639

aio/content/examples/component-interaction/src/app/countdown-parent.component.ts

@@ -39,7 +39,7 @@ export class CountdownLocalVarParentComponent { }
 })
 export class CountdownViewChildParentComponent implements AfterViewInit {
 
-  @ViewChild(CountdownTimerComponent)
+  @ViewChild(CountdownTimerComponent, {static: false})
   private timerComponent: CountdownTimerComponent;
 
   seconds() { return 0; }