[X86] Use hasSingleElement (NFC) (#133040)

Author: kazutakahirata

llvm/lib/Target/X86/X86CmovConversion.cpp

@@ -555,7 +555,7 @@ bool X86CmovConverterPass::checkForProfitableCmovCandidates(
       // This is another conservative check to avoid converting CMOV instruction
       // used with tree-search like algorithm, where the branch is unpredicted.
       auto UIs = MRI->use_instructions(MI->defs().begin()->getReg());
-      if (!UIs.empty() && ++UIs.begin() == UIs.end()) {
+      if (hasSingleElement(UIs)) {
         unsigned Op = UIs.begin()->getOpcode();
         if (Op == X86::MOV64rm || Op == X86::MOV32rm) {
           WorthOpGroup = false;