* New functions: mlirOperationSetAttributeByName, mlirOperationRemoveAttributeByName * Also adds some *IsNull checks and standardizes the rest to use "static inline" form, which makes them all non-opaque and not part of the ABI (which is desirable). * Changes needed to resolve TODOs in npcomp PyTorch capture. Differential Revision: https://reviews.llvm.org/D88946