Fail on unit tests failure (#9862)

* make sure JDK17 tests fail as needed
* set -e to fail on error
diff --git a/kokoro/linux/java_jdk11/build.sh b/kokoro/linux/java_jdk11/build.sh
index 428f854..d73aa7c 100755
--- a/kokoro/linux/java_jdk11/build.sh
+++ b/kokoro/linux/java_jdk11/build.sh
@@ -7,6 +7,9 @@
 # a script to run inside that image.  Then we delegate to the general
 # build_and_run_docker.sh script.
 
+# fail on error
+set -e
+
 # Change to repo root
 cd $(dirname $0)/../../..
 
diff --git a/kokoro/linux/java_jdk17/build.sh b/kokoro/linux/java_jdk17/build.sh
index 9d0ea2b..677245a 100755
--- a/kokoro/linux/java_jdk17/build.sh
+++ b/kokoro/linux/java_jdk17/build.sh
@@ -7,6 +7,9 @@
 # a script to run inside that image.  Then we delegate to the general
 # build_and_run_docker.sh script.
 
+# Fail on error
+set -e
+
 # Change to repo root
 cd $(dirname $0)/../../..