tests: fixes test-vmstate.c compile error on msys2

../tests/test-vmstate.c: In function 'int_cmp':
../tests/test-vmstate.c:884:5: error: unknown type name 'uint'; did you mean 'uInt'?
  884 |     uint ua = GPOINTER_TO_UINT(a);
      |     ^~~~
      |     uInt
../tests/test-vmstate.c:885:5: error: unknown type name 'uint'; did you mean 'uInt'?
  885 |     uint ub = GPOINTER_TO_UINT(b);
      |     ^~~~
      |     uInt
make: *** [Makefile.ninja:5461：tests/test-vmstate.exe.p/test-vmstate.c.obj] 错误 1

Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
Message-Id: <20200905063813.1875-1-luoyonggang@gmail.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

Signed-off-by: Thomas Huth <thuth@redhat.com>