Run PolyGerrit test scripts with bash

Tests are failing with:

+ sh ./polygerrit-ui/app/run_test.sh
./polygerrit-ui/app/run_test.sh: 4: ./polygerrit-ui/app/run_test.sh: [[: not found

Indeed [[ is a bash-ism; maybe the machine's sh stopped being bash.

Change-Id: I09efec7a5018d86b45aaf1fb1952b6764829d092
diff --git a/jenkins/gerrit-bazel-test.sh b/jenkins/gerrit-bazel-test.sh
index 821279a..6214864 100644
--- a/jenkins/gerrit-bazel-test.sh
+++ b/jenkins/gerrit-bazel-test.sh
@@ -20,7 +20,7 @@
 
 echo 'Test PolyGerrit locally'
 echo '----------------------------------------------'
-sh ./polygerrit-ui/app/run_test.sh
+bash ./polygerrit-ui/app/run_test.sh
 
 if [ -z "$SAUCE_USERNAME" ] || [ -z "$SAUCE_ACCESS_KEY" ]
 then
@@ -28,7 +28,7 @@
 else
   echo 'Test PolyGerrit on Sauce Labs'
   echo '----------------------------------------------'
-  WCT_ARGS='--plugin sauce' sh ./polygerrit-ui/app/run_test.sh
+  WCT_ARGS='--plugin sauce' bash ./polygerrit-ui/app/run_test.sh
 fi
 
 exit 0
diff --git a/jenkins/gerrit-bazel-verifier-test.sh b/jenkins/gerrit-bazel-verifier-test.sh
index ab3be98..6549e9a 100644
--- a/jenkins/gerrit-bazel-verifier-test.sh
+++ b/jenkins/gerrit-bazel-verifier-test.sh
@@ -39,13 +39,13 @@
     echo 'Not running local tests because env var "DISPLAY" is not set.'
   else
     echo 'Running local tests...'
-    sh ./polygerrit-ui/app/run_test.sh
+    bash ./polygerrit-ui/app/run_test.sh
   fi
   if [ -z "$SAUCE_USERNAME" ] || [ -z "$SAUCE_ACCESS_KEY" ]
   then
     echo 'Not running on Sauce Labs because env vars are not set.'
   else
     echo 'Running tests on Sauce Labs...'
-    WCT_ARGS='--plugin sauce' sh ./polygerrit-ui/app/run_test.sh
+    WCT_ARGS='--plugin sauce' bash ./polygerrit-ui/app/run_test.sh
   fi
 fi