bazel: mark test only libraries as such.

Change-Id: Ifec05b2fd7f5482a90bcf4a7658d53d1d2ffbcc7
diff --git a/gerrit-gpg/BUILD b/gerrit-gpg/BUILD
index 79f50b1..8cab45c 100644
--- a/gerrit-gpg/BUILD
+++ b/gerrit-gpg/BUILD
@@ -35,6 +35,7 @@
     '//lib/bouncycastle:bcprov-without-neverlink',
   ],
   visibility = ['//visibility:public'],
+  testonly = 1,
 )
 
 junit_tests(
diff --git a/gerrit-server/BUILD b/gerrit-server/BUILD
index dc2375d..de6a06c 100644
--- a/gerrit-server/BUILD
+++ b/gerrit-server/BUILD
@@ -129,6 +129,7 @@
     '//lib/powermock:powermock-module-junit4-common',
   ],
   visibility = ['//visibility:public'],
+  testonly = 1,
 )
 
 PROLOG_TEST_CASE = [
@@ -153,6 +154,7 @@
     '//lib/guice:guice',
     '//lib/prolog:runtime',
   ],
+  testonly = 1,
 )
 
 junit_tests(
@@ -183,6 +185,7 @@
     '//lib/antlr:java_runtime',
   ],
   visibility = ['//visibility:public'],
+  testonly = 1,
 )
 
 junit_tests(
diff --git a/gerrit-util-http/BUILD b/gerrit-util-http/BUILD
index 0e3ac0e..c5d72ba 100644
--- a/gerrit-util-http/BUILD
+++ b/gerrit-util-http/BUILD
@@ -20,6 +20,7 @@
     '//lib/jgit/org.eclipse.jgit:jgit',
   ],
   visibility = ['//visibility:public'],
+  testonly = 1,
 )
 
 junit_tests(