Disable native_coverage for libGLESv2

Bug: http://b/116873221
Bug: http://b/133874658

This is just a work around as we investigate a crash in surfaceflinger
on cuttlefish when coverage is enabled.

Test: surfaceflinger no longer crashes on cuttlefish + coverage builds.
Change-Id: Ib2ee9b159accbe7228d4b2f7661aef9f240d7512
(cherry picked from commit 5d7eb4fb)