Using GL_LINEAR was causing incorrect filtering to occur when copying
the RGBAF32 GPU cache texture on Mali, causing rendering
errors. Switching to GL_NEAREST fixes it.
This is the same bug as bug 1669960, which was believed at the time to
only affect Mali-Gxx. On further testing the bug affects Mali-Txxx
too. Bug 1669960 was worked around at the time by using
glCopyImageSubData instead of glBlitFramebuffer. However, we want to
avoid using glCopyImageSubData on Mali: on Mali-T due to performance
reasons, and on Mali-G due to indefinite hangs. Fixing this filtering
bug allows us to switch both sets of devices to always use
glBlitFramebuffer.
Differential Revision: https://phabricator.services.mozilla.com/D97558
2bdda4c2d6