refactor(compiler): remove all source-level traces to tsc-wrapped (#18966)

- temporarily keeps the old sources under packages/tsc-wrapped
  until the build scripts are changed to use compiler-cli everywhere.
- removes the compiler options `disableTransformerPipeline` that was introduced
  in a previous beta of Angular 5, i.e. the transformer based compiler
  is now always enabled.

PR Close #18966

packages/compiler/test/aot/static_reflector_spec.ts

@@ -7,7 +7,7 @@
  */
 
 import {StaticReflector, StaticSymbol, StaticSymbolCache, StaticSymbolResolver, StaticSymbolResolverHost, core as compilerCore} from '@angular/compiler';
-import {CollectorOptions} from '@angular/tsc-wrapped';
+import {CollectorOptions} from '@angular/compiler-cli/src/metadata/index';
 
 import {MockStaticSymbolResolverHost, MockSummaryResolver} from './static_symbol_resolver_spec';