Fix HWUI Path Cache dangling pointer

When precache, PathTexture is added to PathCache, and it is released after drawn if we want to clean it.
But the PathCache LRU still holds the entry of the PathTexture object. When trim the cache in
the end of each frame, LRU finds that its mListener is not NULL and invoke the functor, however,
mListerer points to the released PathTexture object and is a dangling pointer, thus leads to crash.
Smart pointer don't help here since they only manage scopes, while PathTexture is also controled by
its cleanup field.
The fix is to also remove the LRU entry of PathTexture*, it will also release the texture object
and there won't be texture leaks.

Change-Id: Iaa0621df5dc71532e9e75b38ad94384353930b95