Add overflow flags support to the following ops: * `arith.addi` * `arith.subi` * `arith.muli` Example of new syntax: ``` %res = arith.addi %arg1, %arg2 overflow<nsw> : i64 ``` Similar to existing LLVM dialect syntax ``` %res = llvm.add %arg1, %arg2 overflow<nsw> : i64 ``` Tablegen canonicalization patterns updated to always drop flags, proper support with tests will be added later. Updated LLVMIR translation as part of this commit as it currenly written in a way that it will crash when new attributes added to arith ops otherwise. Discussion https://discourse.llvm.org/t/rfc-integer-overflow-flags-support-in-arith-dialect/76025 --------- Co-authored-by: Yi Wu <yi.wu2@arm.com>