packagegroup-openharmony-tests: Add tests packagegroup

packagegroup-openharmony-tests is intended to aggregate OpenHarmony tests
and to be included in the OpenHarmony test images.

Signed-off-by: Robert Drab <robert.drab@huawei.com>

meta-ohos-core/recipes-core/packagegroups/packagegroup-openharmony-tests.bb

+DESCRIPTION = "OpenHarmony tests package group"
+
+inherit packagegroup
+
+PACKAGES = "\
+	packagegroup-openharmony-tests \
+	"
+
+RDEPENDS_packagegroup-openharmony-tests = "\
+	ohos-xts-acts \
+	"