[MLIR][DRR] Fix inconsistent operand and arg index usage (#139816)
Background issue: #139813
In
[emitEitherOperandMatch()](https://github.com/llvm/llvm-project/blob/e62fc14a5d214f801758b35bdcad0c8efc65e8b8/mlir/tools/mlir-tblgen/RewriterGen.cpp#L774)
we check if `op.getArg(argIndex)` is a `NamedTypeConstraint`:
```cpp
} else if (isa<NamedTypeConstraint *>(op.getArg(argIndex))) {
emitOperandMatch(tree, opName, /*operandName=*/formatv("v{0}", i).str(),
operandIndex,
/*operandMatcher=*/eitherArgTree.getArgAsLeaf(i),
/*argName=*/eitherArgTree.getArgName(i), argIndex,
/*variadicSubIndex=*/std::nullopt);
++operandIndex;
}
```
but in `emitOperandMatch()` we cast on `op.getArg(operandIndex)`, which
is incorrect if the operation has attributes or other non-operand
arguments before its operands.
llvm-project
bae8e1f9 - [MLIR][DRR] Fix inconsistent operand and arg index usage (#139816)
