Merged requested to merge pwithnall/glib:backport-2934-floating-variants-grr-glib-2-74 into glib-2-74
When collecting varargs, ignore the NOCOPY_CONTENTS flag for variants. That is what our docs advice for refcounted types, and it fixes a regression that was inadvertendly introduced when we stopped doing some extra GValue copies.
Includes a test case by Philip Withnall.
Fixes: #2774 (closed)
Trivial backport of !2934 (merged) to