This was discovered by Clusterfuzz on MacOS. The issue was
that is index buffer of a draw indexed call was missing,
causing SwiftShader to access uninitialized memory, leading
to the ASAN crash. The missing index buffer was caused by
DIRTY_BIT_INDEX_BUFFER not being set. This was in turn
caused by ContextVk::flushDirtyGraphicsRenderPass() not
setting dirty bits not included in the dirtyBitMask,
despite needing to be set for future processing.

Bug: chromium:1183068
Bug: chromium:1190493
Change-Id: I65b398d8737b3df5fd51a03a2c8074a774a94a81
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2961690Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>