chore(typescript): Enabled noFallthroughCasesInSwitch

Turned on the noFallthroughCasesInSwitch flag in tsconfig and fixed
a few cases where there were fallthroughs.

tools/@angular/tsc-wrapped/src/collector.ts

@@ -64,9 +64,8 @@ export class MetadataCollector {
         let isConstructor = false;
         switch (member.kind) {
           case ts.SyntaxKind.Constructor:
-            isConstructor = true;
-          // fallthrough
           case ts.SyntaxKind.MethodDeclaration:
+            isConstructor = member.kind === ts.SyntaxKind.Constructor;
             const method = <ts.MethodDeclaration|ts.ConstructorDeclaration>member;
             const methodDecorators = getDecorators(method.decorators);
             const parameters = method.parameters;

tools/@angular/tsc-wrapped/src/evaluator.ts

@@ -176,6 +176,8 @@ export class Evaluator {
             case ts.SyntaxKind.BarBarToken:
               return this.isFoldableWorker(binaryExpression.left, folding) &&
                   this.isFoldableWorker(binaryExpression.right, folding);
+            default:
+              return false;
           }
         case ts.SyntaxKind.PropertyAccessExpression:
           const propertyAccessExpression = <ts.PropertyAccessExpression>node;