[lld-macho] Stabilize symbol order from InterfaceFile

llvm/include/llvm/TextAPI/InterfaceFile.h SymbolsSet uses a
llvm::DenseMap<SymbolsMapKey, Symbol *>, which has a non-deterministic
order. For now, stabilize the order in lld since it is much simpler
than refactoring InterfaceFile.h.

Author: MaskRay

lld/MachO/InputFiles.cpp

@@ -1912,6 +1912,9 @@ DylibFile::DylibFile(const InterfaceFile &interface, DylibFile *umbrella,
       normalSymbols.push_back(symbol);
     }
   }
+  // interface.symbols() order is non-deterministic.
+  llvm::sort(normalSymbols,
+             [](auto *l, auto *r) { return l->getName() < r->getName(); });
 
   // TODO(compnerd) filter out symbols based on the target platform
   for (const auto *symbol : normalSymbols) {

lld/test/MachO/dead-strip.s

@@ -266,12 +266,12 @@
 # UNWIND-NEXT:   g F __TEXT,__text _main
 # UNWIND-NEXT:   g F __TEXT,__text __mh_execute_header
 # UNWIND-NEXT:   *UND* dyld_stub_binder
+# UNWIND-NEXT:   *UND* __ZTIi
 # UNWIND-NEXT:   *UND* ___cxa_allocate_exception
+# UNWIND-NEXT:   *UND* ___cxa_begin_catch
 # UNWIND-NEXT:   *UND* ___cxa_end_catch
-# UNWIND-NEXT:   *UND* __ZTIi
 # UNWIND-NEXT:   *UND* ___cxa_throw
 # UNWIND-NEXT:   *UND* ___gxx_personality_v0
-# UNWIND-NEXT:   *UND* ___cxa_begin_catch
 # UNWIND-NOT:    GCC_except_table0
 
 ## If a dead stripped function has a strong ref to a dylib symbol but