Handle AllAlpha and AllBeta in SetFeatureGateDuringTest

hack/verify-test-featuregates.sh

@@ -30,7 +30,7 @@ cd "${KUBE_ROOT}"
 rc=0
 
 # find test files accessing the mutable global feature gate or interface
-direct_sets=$(find -L . -name '*_test.go' -exec grep -Hn 'MutableFeatureGate' {} \; 2>/dev/null) || true
+direct_sets=$(git grep MutableFeatureGate -- '*_test.go') || true
 if [[ -n "${direct_sets}" ]]; then
   echo "Test files may not access mutable global feature gates directly:" >&2
   echo "${direct_sets}" >&2
@@ -42,7 +42,7 @@ if [[ -n "${direct_sets}" ]]; then
 fi
 
 # find test files calling SetFeatureGateDuringTest and not calling the result
-missing_defers=$(find -L . -name '*_test.go' -exec grep -Hn 'SetFeatureGateDuringTest' {} \; 2>/dev/null | grep -E -v "defer .*\\)\\(\\)$") || true
+missing_defers=$(git grep "\\.SetFeatureGateDuringTest" -- '*_test.go' | grep -E -v "defer .*\\)\\(\\)$") || true
 if [[ -n "${missing_defers}" ]]; then
   echo "Invalid invocations of featuregatetesting.SetFeatureGateDuringTest():" >&2
   echo "${missing_defers}" >&2