fix the CI test failure

Author: YixingZhang007

llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp

@@ -244,7 +244,7 @@ std::string lookupBuiltinNameHelper(StringRef DemangledCall,
       "SDotKHR|SUDotKHR|SDotAccSatKHR|UDotAccSatKHR|SUDotAccSatKHR|"
       "ReadClockKHR|SubgroupBlockReadINTEL|SubgroupImageBlockReadINTEL|"
       "SubgroupImageMediaBlockReadINTEL|SubgroupImageMediaBlockWriteINTEL|"
-      "Convert|Round"
+      "Convert|Round|"
       "UConvert|SConvert|FConvert|SatConvert)[^_]*)(_R[^_]*_?(\\w+)?.*)?");
   std::smatch Match;
   if (std::regex_match(BuiltinName, Match, SpvWithR) && Match.size() > 1) {