[Asm] Finish matching once end of formal and actual lists reached (NFC)

This is NFC, as the matcher would continue looping up to the maximum
number of operands with no effect, but this should improve performance a
bit, and makes the debug trace clearer.

Differential revision: https://reviews.llvm.org/D36744

llvm-svn: 318769

llvm/utils/TableGen/AsmMatcherEmitter.cpp

@@ -3323,6 +3323,7 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
     OS << "          }\n";
     OS << "        } else {\n";
     OS << "          DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \"but formal operand not required\\n\");\n";
+    OS << "          break;\n";
     OS << "        }\n";
     OS << "        continue;\n";
   } else {