Don't handle vendor-specific SPIR-V instructions
Don't handle vendor-specific SPIR-V instructions

SwiftShader should not implement any vendor-specific extensions, so
their opcode enums can be removed.

Bug: b/178477034
Change-Id: Ifb034493aaa51ee2bf93d084773d7b412db704e6
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/60248
Kokoro-Result: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Tested-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>
Reviewed-by: Alexis Hétu <1c7141772178a7e80858c3db5052b328076f08f4@google.com>

google/swiftshader,google/swiftshader,google/swiftshader