AnimCursorCreate allocates an OsTimer even if the cursor is never
displayed. AnimCurUnrealizeCursor releases the retained frame cursors
but does not release that timer, leaking 40 bytes per animated cursor
on the tested x86_64 build.
Free the timer with the frame references on screen zero, and clear the
pointer. This cleanup runs when the final cursor reference is released.
The leak was reproduced with LeakSanitizer on an XLibre 25.1.9-based
test server. With the fix, all 90 focused native ASan/UBSan checks
pass with leak detection enabled and GLX disabled, including unused
animated cursors and repeated displayed cursor replacement.
Signed-off-by: David <david@code.contractors>