Pretty much the same as https://gitlab.winehq.org/wine/wine/-/merge_requests/1843, but on win32u side, to figure and validate the syscall entry signatures.
-- v5: win32u/tests: Test NtUserGetPointerInfoList syscall signature. win32u/tests: Test NtUserIsMouseInPointerEnabled syscall. win32u/tests: Test NtUserEnableMouseInPointer syscall. win32u: Stub NtUserGetPointerInfoList syscall. win32u: Stub NtUserIsMouseInPointerEnabled syscall. win32u: Move NtUserEnableMouseInPointer from user32. include: Declare some NtUser pointer related syscalls.