[SPIRV] add IR regularization pass

The patch adds the regularization pass that prepare LLVM IR for
the IR translation. It also contains following changes:
- reduce indentation, make getNonParametrizedType, getSamplerType,
getPipeType, getImageType, getSampledImageType static in SPIRVBuiltins,
- rename mayBeOclOrSpirvBuiltin to getOclOrSpirvBuiltinDemangledName,
- move isOpenCLBuiltinType, isSPIRVBuiltinType, isSpecialType from
SPIRVGlobalRegistry.cpp to SPIRVUtils.cpp, renaming isSpecialType to
isSpecialOpaqueType,
- implment getTgtMemIntrinsic() in SPIRVISelLowering,
- add hasSideEffects = 0 in Pseudo (SPIRVInstrFormats.td),
- add legalization rule for G_MEMSET, correct G_BRCOND rule,
- add capability processing for OpBuildNDRange in SPIRVModuleAnalysis,
- don't correct types of registers holding constants and used in
G_ADDRSPACE_CAST (SPIRVPreLegalizer.cpp),
- lower memset/bswap intrinsics to functions in SPIRVPrepareFunctions,
- change TargetLoweringObjectFileELF to SPIRVTargetObjectFile
in SPIRVTargetMachine.cpp,
- correct comments.
5 LIT tests are added to show the improvement.

Differential Revision: https://reviews.llvm.org/D133253



Co-authored-by: Aleksandr Bezzubikov <zuban32s@gmail.com>
Co-authored-by: Michal Paszkowski <michal.paszkowski@outlook.com>
Co-authored-by: Andrey Tretyakov <andrey1.tretyakov@intel.com>
Co-authored-by: Konrad Trifunovic <konrad.trifunovic@intel.com>