Add tracking of shared memory declarations in compute shaders.

Test:
  angle_deqp_gles31_tests --gtest_filter=dEQP.GLES31/functional_debug_negative_coverage_callbacks_compute_exceed_shared_memory_size_limit

Bug: 4173
Change-Id: If2a86d467a82f73fa5b2ee0ced752701acfe1872
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1934653
Commit-Queue: Courtney Goeltzenleuchter <courtneygo@google.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>