Pass filename instead of piping contents through stdin to dart format in PRESUBMIT.py
Pass filename instead of piping contents through stdin to dart format in
PRESUBMIT.py

FIXES=#46600

Change-Id: I69358185b5a8dfc863f17cd4beb0209592d3be09
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/206681
Reviewed-by: Bob Nystrom <afede3a9ebedb865bee78398feff6fbe97068f17@google.com>
Commit-Queue: Ben Konyi <67ffcaedcc3dc3d87dddb9627b72dd41756b31b1@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk