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

[olista01]

Summary

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.

[olista01]

Now with diff context.

[olista01]

Ping

[rengolin]

LGTM, thanks!

llvm/trunk/utils/TableGen/AsmMatcherEmitter.cpp

if (ReportMultipleNearMisses) {
     OS << "            DEBUG_WITH_TYPE(\n";
     OS << "                \"asm-matcher\",\n";
     OS << "                dbgs() << \"second invalid operand, giving up on this opcode\\n\");\n";
     OS << "            MultipleInvalidOperands = true;\n";
     OS << "            break;\n";
     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 {
     OS << "        OperandsValid = (Formal == InvalidMatchClass) || isSubclass(Formal, OptionalMatchClass);\n";
     OS << "        if (!OperandsValid) ErrorInfo = ActualIdx;\n";
     if (HasOptionalOperands) {
       OS << "        OptionalOperandsMask.set(FormalIdx, " << MaxNumOperands
          << ");\n";