[tools][cts] Fix "no data for query 'webgpu:shader'" error

If a test is removed from CTS that had a 'RetryOnFailure' expectation, then this would cause an error to be raised.
Just ignore this situation. Expectations for removed tests will automatically get cleaned up in the updater.expatation() logic.

Change-Id: I18f56a7aaac4a758b0bb95ec3286410627ada6eb
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/146903
Commit-Queue: Ben Clayton <[email protected]>
Kokoro: Ben Clayton <[email protected]>
Auto-Submit: Ben Clayton <[email protected]>
Reviewed-by: Austin Eng <[email protected]>

Author: ben-clayton

tools/src/cts/expectations/update.go

@@ -282,6 +282,12 @@ func (u *updater) preserveRetryOnFailures() error {
 
 			glob, err := u.qt.tree.Glob(q)
 			if err != nil {
+				if errors.As(err, &query.ErrNoDataForQuery{}) {
+					// No results for this RetryOnFailure expectation.
+					// Flaky tests might have been removed from the CTS.
+					// These expectations will be automatically removed by updater.expectation()
+					continue
+				}
 				return err
 			}
 			for _, indices := range glob {