[mlir] Generalize intrinsic builders in the LLVM dialect definition
All LLVM IR intrinsics are constructed in a similar way. The ODS definition of
the LLVM dialect in MLIR also lists multiple intrinsics, many of which
reproduce the same (or similar enough) code stanza to translate the MLIR
operation into the LLVM IR intrinsic. Provide a single base class containing
parameterizable code to build LLVM IR intrinsics given their name and the lists
of overloadable operands and results. Use this class to remove (almost)
duplicate translations for intrinsics defined in LLVMOps.td.
Differential Revision: https://reviews.llvm.org/D74889