fix(perf): support prod mode again

After splitting the facades into multiple modules,
enabling prod mode for code had no effect for the compiler.

Also in a change between RC1 and RC2 we created the `CompilerConfig`
via a provider with `useValue` and not via a `useFactory`, which reads
the prod mode too early.

Closes #9318
Closes #8508
Closes #9318

modules/@angular/platform-browser/src/security/style_sanitizer.ts

@@ -1,8 +1,10 @@
+import {isDevMode} from '@angular/core';
+
 import {getDOM} from '../dom/dom_adapter';
-import {assertionsEnabled} from '../facade/lang';
 
 import {sanitizeUrl} from './url_sanitizer';
 
+
 /**
  * Regular expression for safe style values.
  *
@@ -81,7 +83,7 @@ export function sanitizeStyle(value: string): string {
     return value;  // Safe style values.
   }
 
-  if (assertionsEnabled()) getDOM().log('WARNING: sanitizing unsafe style value ' + value);
+  if (isDevMode()) getDOM().log('WARNING: sanitizing unsafe style value ' + value);
 
   return 'unsafe';
 }