[SPIRV] Update the way how llvm-spirv is used

[AlexeySachkov]

KhronosGroup/SPIRV-LLVM-Translator has been updated to support mechanism to disable/enable SPIR-V extensions and to control the SPIR-V version which is used during translation.

You can find full list of changes and related documentation in KhronosGroup/SPIRV-LLVM-Translator#244

Here is the summary of what should we do on our side:

• drop usage of -spirv-no-deref-attr in favor of new -spirv-max-version option. Here is corresponding commit in the translator.
• explicitly enable required extension (or simply use +all), otherwise, we will lost support of nsw/nuw attributes, sub-groups, FPGA attributes. Examples can be found here and here

Tagging @bader, @mdtoguchi and @vladimirlaz: FYI

This is not critical right now, but it should be done as soon as we update our copy of KhronosGroup/SPIRV-LLVM-Translator to the corresponding revision (3f0fd561).

[AlexeySachkov]

Fixed by #533