Fixed issues/improvements:

• Fix send payload coalescing when a source is larger than two GRFs.
• Group instructions together for performance.
• Check dangling constant users for Function/Global symbols, before iterating through the user list.
• Add the debug flags to limit number of constants to fold.
• Fix 64-bit multiplication emulation where the result is one of the factors.
• Fix translation of operation parameter of OpGroupNonUniformBallotBitCount.
• Verification pass for explicit variable split phase. Pass can be enabled using -verifysplit switch.
• Enable integer mad by default for OCL.
• Support function symbols used by Constants. MemOpt may combine multiple function address symbols into a single constant for load/store. Updating codegen to support this.
• Optimize indirect calls with function groups using LLVM !callees metadata. Fixed a few existing bugs, and removed the pass from OptimizeIR.
• Checking in FindInterestingConstants changes to return constants in sorted order.
• Fix translation of BallotBitCOunt in SPIRV Reader.
• Skip bank conflict hint for split variables to increase coalescing chances.
• Fix ASR offset for signed extend 32-bit value to 64-bit.
• Fix incorrect specialization constants reuse by subsequent SPIR-V modules.
• Skip trivial RA when variable split is done to avoid generating extra movs.
• Fix specialization constants for linking path.
• Enable explicit variable splitting and disable existing local split.
• Promote to stateful if GEP is not existed and address type is DW-aligned.
• Bail out from mad optimization if one of the operand is INF.
• And other fixes and performance improvements.

Ubuntu 18.04 binary packages for LLVM10/Clang10 are included.