fix(@ngtools/webpack): getCurrentDirectory should not return a devk…

…it path

At the moment we are leaking devkit paths as `getCurrentDirectory` is used by the ngtsc compiler if no `rootDir` directories is provided.

`getCurrentDirectory` is also used to contruct the `rootDirs` option which is causing this to be incorrect as under Windows as `rootDirs` will be have an invalid value example: `/c/foo/bar`

This PR complements angular/angular#29151

**Note** that this currently works because we are normalizing paths with posix seperators and is mimicking the behaviour of the logical file system used by the ngtsc.

Fixes: #13849

packages/ngtools/webpack/src/compiler_host.ts

@@ -314,7 +314,7 @@ export class WebpackCompilerHost implements ts.CompilerHost {
   }
 
   getCurrentDirectory(): string {
-    return this._basePath;
+    return workaroundResolve(this._basePath);
   }
 
   getCanonicalFileName(fileName: string): string {