[ORC-RT] Make ExecutorAddrDiff an alias for uint64_t.

Unlike ExecutorAddr, there's limited value to having a distinct type for
ExecutorAddrDiff, and it's occasionally awkward to work with. The corresponding
LLVM type (llvm::orc::ExecutorAddrDiff) was already made a type-alias in
9e2cfb061a882.

GitOrigin-RevId: 4c434831865f0ce95bc396e8de786a0d21bbfa7a
1 file changed