`ts.server.ServerHost.resolvePath()` is different from Angular's
`FileSystem.resolve()` because the signature of the former is
```ts
resolvePath(path: string): string; // ts.server.ServerHost
```
whereas the signature of the latter is
```ts
resolve(...paths: string[]): AbsoluteFsPath; // FileSystem on compiler-cli
```
The current implementation calls `path.join()` to concatenate all the input
paths and pass the result to `ts.server.ServerHost.resolvePath()`, but doing
so results in filenames like
```
/foo/bar/baz/foo/bar/baz/tsconfig.json
```
if both input paths are absolute.
`ts.server.ServerHost` should not be used to implement the
`resolve()` method expected by Angular's `FileSystem`.
We should use Node's `path.resolve()` instead, which will correctly collapse
the absolute paths.
Fix https://github.com/angular/vscode-ng-language-service/issues/1035
PR Close#40242
Keen Yee Liau