Buck: Don't use --no-results-cache on older Buck versions

Older Buck versions don't support that option.

Change-Id: Iff174d2fbeed7263ceeef8dc52c76b6d60d0db85
diff --git a/jenkins/gerrit-buck-test.sh b/jenkins/gerrit-buck-test.sh
index 1a4bcb3..827c43b 100644
--- a/jenkins/gerrit-buck-test.sh
+++ b/jenkins/gerrit-buck-test.sh
@@ -5,6 +5,12 @@
 SOURCE_LEVEL=$(grep "source_level" .buckconfig || echo "source_level=7")
 . set-java.sh $(echo $SOURCE_LEVEL | cut -d '=' -f 2 | tr -d '[[:space:]]')
 
+BUCK_OPTIONS="--no-results-cache"
+if ([ "$TARGET_BRANCH" == "stable-2.9" ])
+then
+  BUCK_OPTIONS="--all"
+fi
+
 echo 'Test in default DB mode'
 echo '----------------------------------------------'
-buck test --no-results-cache --exclude flaky
+buck test $BUCK_OPTIONS --exclude flaky
diff --git a/jenkins/gerrit-buck-verifier-test.sh b/jenkins/gerrit-buck-verifier-test.sh
index 6c5434d..f84ee80 100644
--- a/jenkins/gerrit-buck-verifier-test.sh
+++ b/jenkins/gerrit-buck-verifier-test.sh
@@ -9,8 +9,14 @@
 echo "Test with mode=$MODE"
 echo '----------------------------------------------'
 
+BUCK_OPTIONS="--no-results-cache"
+if ([ "$TARGET_BRANCH" == "stable-2.9" ])
+then
+  BUCK_OPTIONS="--all"
+fi
+
 if [[ "$MODE" == *"reviewdb"* ]]
 then
-  buck test --no-results-cache --exclude flaky
+  buck test $BUCK_OPTIONS --exclude flaky
 fi