tests: Skip POSIX-only tests on Windows

test-rfifolock and test-vmstate only build on POSIX hosts.  Exclude them
if building for Windows.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NStefan Weil <sw@weilnetz.de>
Signed-off-by: NAndreas Färber <afaerber@suse.de>

tests/Makefile

@@ -35,7 +35,7 @@ check-unit-y += tests/test-visitor-serialization$(EXESUF)
 check-unit-y += tests/test-iov$(EXESUF)
 gcov-files-test-iov-y = util/iov.c
 check-unit-y += tests/test-aio$(EXESUF)
-check-unit-y += tests/test-rfifolock$(EXESUF)
+check-unit-$(CONFIG_POSIX) += tests/test-rfifolock$(EXESUF)
 check-unit-y += tests/test-throttle$(EXESUF)
 gcov-files-test-aio-$(CONFIG_WIN32) = aio-win32.c
 gcov-files-test-aio-$(CONFIG_POSIX) = aio-posix.c
@@ -59,7 +59,7 @@ check-unit-y += tests/test-bitops$(EXESUF)
 check-unit-y += tests/test-qdev-global-props$(EXESUF)
 check-unit-y += tests/check-qom-interface$(EXESUF)
 gcov-files-check-qom-interface-y = qom/object.c
-check-unit-y += tests/test-vmstate$(EXESUF)
+check-unit-$(CONFIG_POSIX) += tests/test-vmstate$(EXESUF)
 
 check-block-$(CONFIG_POSIX) += tests/qemu-iotests-quick.sh