Translate OpOrdered and OpUnordered to fcmp instructions

Instead of translating this instructions to OCL builtin calls, use core llvm
fcmp instructions for better code preservation during translation.

fixed tests

separated fcmp test from OCL builtins

Original commit:
KhronosGroup/SPIRV-LLVM-Translator@a10c012

Author: DmitryBushev

llvm-spirv/lib/SPIRV/SPIRVReader.cpp

@@ -600,7 +600,7 @@ SPIRVToLLVM::transValue(const std::vector<SPIRVValue *> &BV, Function *F,
 
 bool SPIRVToLLVM::isSPIRVCmpInstTransToLLVMInst(SPIRVInstruction *BI) const {
   auto OC = BI->getOpCode();
-  return isCmpOpCode(OC) && !(OC >= OpLessOrGreater && OC <= OpUnordered);
+  return isCmpOpCode(OC) && OC != OpLessOrGreater;
 }
 
 void SPIRVToLLVM::setName(llvm::Value *V, SPIRVValue *BV) {