Possible memory leak in test-tree-magic.c
A Coverity Scan discovered that there's possible to leak memory previously assigned to a variable at:
https://gitlab.freedesktop.org/xdg/shared-mime-info/-/blob/815b520eb01992a05d41a5434f1227a8be101e15/src/test-tree-magic.c#L142
It can happen when the parts
array contains more than one value not know to the preceding code.