feat(compiler): support a non-null postfix assert (#16672)

Template expressions can now use a post-fix `!` operator
that asserts the target of the operator is not null. This is
similar to the TypeScript non-null assert operator. Expressions
generated in factories will be generated with the non-null assert
operator.

Closes: #10855

packages/compiler/test/aot/test_util.ts

@@ -44,6 +44,7 @@ export const settings: ts.CompilerOptions = {
   removeComments: false,
   noImplicitAny: false,
   skipLibCheck: true,
+  strictNullChecks: true,
   lib: ['lib.es2015.d.ts', 'lib.dom.d.ts'],
   types: []
 };