0946357650
Reverts: flutter/engine#51685
Initiated by: matanlurey
Reason for reverting: goldctl does not disambiguate negatives from untriaged images (see 9b9adad080/gold-client/cmd/goldctl/cmd_imgtest_test.go (L325)).
Original PR Author: matanlurey
Reviewed By: {mdebbar, gaaclarke}
This change reverts the following previous change:
`flutter/engine`-side fix for https://github.com/flutter/flutter/issues/145043.
- Before this PR, if a negative image was encountered, we'd silently pass pre-submit, merge, and turn the tree red.
- After this PR, a negative image both makes pre and post-submit red.
Added tests, and fixed up some unrelated tests that were accidentally setting `pid` instead of `exitCode`. Oops!
/cc @zanderso and @eyebrowsoffire (current engine sheriff).