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, mListener 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