`create_srcjar = false` was needed during the transition to moving
R.java generation to android_library targets. Now this variable is
unused (the variable is asserted to be false), clean up all references.
Bug: chromium:1073476
Change-Id: I4c09ea05ded27ea2360392aacbce036bc1a2f928
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/185160
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Mohamed Heikal <mheikal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#32178}