squisher: Get rid of it.

The pngcrush tool does not add any noticeable value any more, such that it justifies the extra build time: 240MB vs 238MB.
The build.prop changes are now no ops, since the key for ro.kernel.android.checkjni no longer exists.
Changing the ro.build.type from eng to user is also a no op, since CM is now userdebug.
Deleting bins is also unncessary now.
Stripping modules is also unnecessary now. (plenty of space)

At this point, I think we can just symlink $OUTFILE to $OTAPACKAGE, and not even bother
with a copy.

Change-Id: I431ac6425dedb6cd02eb2d31fc9ff82b49df9f50