spirv-opt: Add --graphics-robust-access
Clamps access chain indices so they are always
in bounds.
Assumes:
- Logical addressing mode
- No runtime-array-descriptor-indexing
- No variable pointers
Adds stub code for clamping coordinate and samples
for OpImageTexelPointer.
Adds SinglePassRunAndFail optimizer test fixture.
Android.mk: add source/opt/graphics_robust_access_pass.cpp
Adds Constant::GetSignExtendedValue, Constant::GetZeroExtendedValue
