[NFC][lld] Inclusive language: change master file to merged file

[quinnp]

Summary

[NFC] As part of using inclusive language within the llvm project, this patch
replaces master with merged in these comments.

[thakis]

lg, but this code will be deleted soon anyways

lld/lib/ReaderWriter/MachO/GOTPass.cpp

for (const DefinedAtom *atom : mergedFile.defined()) {
           const DefinedAtom *gotEntry = makeGOTEntry(target);
           const_cast<Reference *>(ref)->setTarget(gotEntry);
           // Update reference kind to reflect that target is now a GOT entry.
           _archHandler.updateReferenceToGOT(ref, true);
         }
       }
     }
 
-    // Sort and add all created GOT Atoms to master file
+    // Sort and add all created GOT Atoms to merged file
     std::vector<const GOTEntryAtom *> entries;
     entries.reserve(_targetToGOT.size());
     for (auto &it : _targetToGOT)
       entries.push_back(it.second);
     std::sort(entries.begin(), entries.end(),
               [](const GOTEntryAtom *left, const GOTEntryAtom *right) {
       return (left->slotName().compare(right->slotName()) < 0);
     });

lld/lib/ReaderWriter/MachO/ShimPass.cpp

llvm::Error perform(SimpleFile &mergedFile) override {
     for (auto element : _targetToShim) {
       shims.push_back(element.second);
     }
     std::sort(shims.begin(), shims.end(),
               [](const DefinedAtom *l, const DefinedAtom *r) {
                 return (l->name() < r->name());
               });
 
-    // Add all shims to master file.
+    // Add all shims to merged file.
     for (const DefinedAtom *shim : shims)
       mergedFile.addAtom(*shim);
 
     return llvm::Error::success();
   }
 
 private: