[clang] [CIR] Upstream Exception Attr in CallOp (PR #164964)

[Amr Hesham via cfe-commits]

================
@@ -729,9 +735,15 @@ static mlir::ParseResult parseCallCommon(mlir::OpAsmParser &parser,
   if (parser.parseRParen())
     return mlir::failure();
 
-  if (parser.parseOptionalKeyword("nothrow").succeeded())
+  llvm::SMLoc optionalNothrowLoc = parser.getCurrentLocation();
+  if (parser.parseOptionalKeyword("nothrow").succeeded()) {
+    if (hasExceptions)
+      return parser.emitError(
+          optionalNothrowLoc,
+          "should have either `exception` or `nothrow`, but not both");
----------------
AmrDeveloper wrote:

I think yes, this attribute was used as a marker to mark CallOp as invoked, and in TryOp, we convert it to TryCallOp, but I think we can use the absence of `nothrow` as a condition, the only difference will be the IR

In the incubator 

```
cir.try {
   %0 = cir.call exception @foo() : () -> !s32i
   cir.yield
}
```

to 

```
cir.try {
   %0 = cir.call @foo() : () -> !s32i
   cir.yield
}
```

https://github.com/llvm/llvm-project/pull/164964