fix(@ngtools/webpack): resolve file name before invalidating cached files (#4384)

Fix WebpackCompilerHost's cache invalidation behavior on Windows
systems. Previously, no call to _resolve was made, causing paths with
backslashes not to match the file cache.

Fixes #4422
Fixes #4345
Fixes #4338

Author: msmorgan

packages/@ngtools/webpack/src/compiler_host.ts

@@ -187,6 +187,7 @@ export class WebpackCompilerHost implements ts.CompilerHost {
   }
 
   invalidate(fileName: string): void {
+    fileName = this._resolve(fileName);
     if (fileName in this._files) {
       this._files[fileName] = null;
       this._changedFiles[fileName] = true;