message: fix(compiler-cli): normalize mock Windows file paths correctly
  Since the `MockFileSystemWindows` is case-insensitive, any
  drive path that must be added to a normalized path should be lower
  case to make the path canonical.
  PR Close
diff: @@ -42,6 +42,6 @@ export class MockFileSystemWindows extends MockFileSystem {
  }
  normalize<T extends PathString>(path: T): T {
  - return path.replace(/^[\/\\]/i, 'C:/').replace(/\\/g, '/') as T;
  + return path.replace(/^[\/\\]/i, 'c:/').replace(/\\/g, '/') as T;
  }
  }
  