validate width*height doesn't overflow in image file

width*heigh*1.5 is used to derive max input buffer size for codecs.
This must not overflow.

bug: 145521781
test: run 'stagefright -s -t /sdcard/poc.heic' as in the bug,
stagefright should still fail, but it shouldn't crash in
mediaextractor.

Change-Id: I31ab8e150d348f6637d8212780832045d26991a0