This patch adds missing checks for querying GL_COMPUTE_WORK_GROUP_SIZE
by glGetProgramiv.

When querying GL_COMPUTE_WORK_GROUP_SIZE, an INVALID_OPERATION error
should be generated when this program hasn't been linked successfully
or it doesn't contain any objects to form a compute shader.

BUG=angleproject:2324
TEST=angle_end2end_tests
     dEQP-GLES31.functional.debug.negative_coverage.get_error.compute.invalid_program_query

Change-Id: I13dcebef8a0abede5c18a038d4cf915ee4164e2e
Reviewed-on: https://chromium-review.googlesource.com/933627
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>