go/analysis/analysistest: Raise error when edited file cannot be formatted

There are instances when the diagnostics are reported correctly by the
analyzer, but the suggested fixes are wrong, and result in code that
cannot be formatted by `format.Source` (due to errors in the edited code).
Right now, in those cases, the tests pass despite the format errors.
This commit fixes that.

Signed-off-by: Sourya Vatsyayan <[email protected]>

Author: sourya

go/analysis/analysistest/analysistest.go

@@ -209,6 +209,7 @@ func RunWithSuggestedFixes(t Testing, dir string, a *analysis.Analyzer, patterns
 
 			formatted, err := format.Source([]byte(out))
 			if err != nil {
+				t.Errorf("Could not format edited file %s. Error: %s", file.Name(), err)
 				continue
 			}
 			if want != string(formatted) {