Enable SPIRV validation by default

This change makes IGC to pass list of supported extensions to Khronos
SPIRV-LLVM Translator, so that SPIRV can be validated and proper error
messages can be generated for unsupported extensions.

Author: aratajew

IGC/common/igc_flags.h

@@ -1304,7 +1304,7 @@ DECLARE_IGC_REGKEY(bool, ForcePrefetchToL1Cache, false, "Forces standard builtin
 DECLARE_IGC_REGKEY(bool, DisablePrefetchToL1Cache, false, "Disable prefetch to L1 cache", true)
 DECLARE_IGC_REGKEY(bool, ForceXYZworkGroupWalkOrder, true, "Force X/Y/Z WorkGroup walk order", true)
 DECLARE_IGC_REGKEY(
-    bool, ValidateSPIRVExtensionSupport, false,
+    bool, ValidateSPIRVExtensionSupport, true,
     "When enabled, validate each SPIR-V OpExtension against device support and fail compilation if any are "
     "unsupported. Disabled by default until the supported extension list in SPIRVExtensions.td is complete.",
     true)