Combine build invocations for better parallelism

This should reduce cycle time by ~ 1 minute.

Change-Id: Ice93f8ffc154cda9f27a40ee2248d45fbed42c4f
diff --git a/jenkins/gerrit-bazel-build.sh b/jenkins/gerrit-bazel-build.sh
index 443cdf8..3fcb13e 100644
--- a/jenkins/gerrit-bazel-build.sh
+++ b/jenkins/gerrit-bazel-build.sh
@@ -5,6 +5,4 @@
 
 export BAZEL_OPTS="--spawn_strategy=standalone --genrule_strategy=standalone"
 
-bazel build $BAZEL_OPTS plugins:core
-bazel build $BAZEL_OPTS release
-bazel build $BAZEL_OPTS api
+bazel build $BAZEL_OPTS plugins:core release api