The current value of kDefaultDescriptorPoolMaxSets is 2048, which
allocates too much memory on a Pixel device, causing Android's low
memory killer to terminate dEQP (leading to a test failure). This change
reduces the value of kDefaultDescriptorPoolMaxSets to 128 to reduce the
memory usage during the test. We suspect a later change may be required
to dynamically grow the descriptor pools and update the recycling
behavior.

dEQP-EGL.functional.multicontext.non_shared_clear

Bug: angleproject:3056
Change-Id: I8a681b509823956a58d6c08f64a23203458e075e
Reviewed-on: https://chromium-review.googlesource.com/c/1454280Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Tim Van Patten <timvp@google.com>