Adjust dump file location under Android

Adjust dump file location under Android

* java/org/gnu/emacs/EmacsApplication.java (EmacsApplication)
<apkFileName>: New field.
(getApkFile): Move from EmacsService.java.
(findDumpFile): If the dump file is older than the APK, delete
it irrespective of whether the checksums agree.
(onCreate): Initialize apkFileName.

* java/org/gnu/emacs/EmacsService.java (onCreate): Use
EmacsApplication.apkFileName.

* src/android.c (android_on_low_memory): Correct arguments to
Fclear_image_cache.

* src/image.c (Fclear_image_cache): Check that animation_cache
is always a cons.