Add missing bazel dependency to benchmarks

Change-Id: I330cbdbe7fdd2e3523cfc555adb15b577e858083

org.eclipse.jgit.benchmarks/BUILD

diff --git a/org.eclipse.jgit.benchmarks/BUILD b/org.eclipse.jgit.benchmarks/BUILD
index ecd268c..6198e4d 100644
--- a/org.eclipse.jgit.benchmarks/BUILD
+++ b/org.eclipse.jgit.benchmarks/BUILD
@@ -7,9 +7,11 @@
 jmh_java_benchmarks(
     name = "benchmarks",
     srcs = SRCS,
+    testonly = 1,
     deps = [
         "//lib:javaewah",
         "//lib:slf4j-api",
         "//org.eclipse.jgit:jgit",
+        "//org.eclipse.jgit.junit:junit",
     ],
 )