If a static error test contains "[web]" error markers, this runs them
on DDC and dart2js, parses the output, and tests that the compilers
report the expected errors.
Change-Id: I8b846f75828a0078f61c2fc1f3da0a4a587349cb
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/158100
Commit-Queue: Bob Nystrom <rnystrom@google.com>
Auto-Submit: Bob Nystrom <rnystrom@google.com>
Reviewed-by: Srujan Gaddam <srujzs@google.com>