SPIRV-Headers changes for SPV_QCOM_image_processing2.
add a new capability TextureBlockMatch2QCOM
add a new decoration BlockMatchSamplerQCOM
add four new instructions, OpImageBlockMatchWindowSSDQCOM, OpImageBlockMatchWindowSADQCOM, OpImageBlockMatchGatherSSDQCOM and OpImageBlockMatchGatherSADQCOM
SPIRV-Headers changes for SPV_QCOM_image_processing2.