[BOLT] Use llvm::upper_bound (NFC) (#140174)

Author: kazutakahirata

bolt/lib/Core/DIEBuilder.cpp

@@ -437,10 +437,10 @@ getUnitForOffset(DIEBuilder &Builder, DWARFContext &DWCtx,
       // This is a work around for XCode clang. There is a build error when we
       // pass DWCtx.compile_units() to llvm::upper_bound
       std::call_once(InitVectorFlag, initCUVector);
-      auto CUIter = std::upper_bound(CUOffsets.begin(), CUOffsets.end(), Offset,
-                                     [](uint64_t LHS, const DWARFUnit *RHS) {
-                                       return LHS < RHS->getNextUnitOffset();
-                                     });
+      auto CUIter = llvm::upper_bound(CUOffsets, Offset,
+                                      [](uint64_t LHS, const DWARFUnit *RHS) {
+                                        return LHS < RHS->getNextUnitOffset();
+                                      });
       CU = CUIter != CUOffsets.end() ? (*CUIter) : nullptr;
     }
     return CU;