Add gson jar contents to javac builds.
Add gson jar contents to javac builds.

PiperOrigin-RevId: 381016999
Change-Id: I564c05f5513e233640defddaac3bfdd8a934b71f

GoogleCloudPlatform/cloud-debug-java,GoogleCloudPlatform/cloud-debug-java,GoogleCloudPlatform/cloud-debug-java,GoogleCloudPlatform/cloud-debug-java