[mlir][StandardToSPIRV] Handle i1 case for lowering memref.load/store op

This patch unconditionally converts i1 types to i8 types on memrefs. If the
extensions or capabilities are not met, they will be converted to i32. Hence the
logic in IntLoadPattern and IntStorePattern are also updated.

Also added the implementation of SPIRVTypeConverter::getOptions().

Reviewed By: antiagainst

Differential Revision: https://reviews.llvm.org/D99724