AAPT2: Workaround for findViewById with package ID > 0x7f

The entire View code base checks IDs against View.NO_ID except
findViewById(), which checks to see if the ID is negative.

Any package ID > 0x7f is interpreted as a negative number in Java
(no unsigned ints), so this check prevents the use of IDs > 0x7f.

findViewById is final, so support library workarounds are not possible.

Instead, IDs (@id/foo) are just sentinels, their values don't matter.
If building for pre-O devices, rewrite any references to these IDs of
the for 0xPPTTEEEE, where PP > 7f, to 0x7fPPEEEE.

The symbol table will check for potential collisions against the base
APK, so this should be safe.

Bug: 37498913
Test: manual
Change-Id: Ife3bbd29db287757ef8a2ffd83053d97f1db2613