Fix IncompatibleClassChangeError when hardening Compose apps with --k…

[blackandwhiteforzj]

Root cause

With --keep-classes, splitDex re-partitions each dex with dexlib2 (read →
write), splitting classes into a separate "keep" dex and reorganizing the
remaining dex. This changes the dex membership/type tables of Compose classes
and breaks ART's cross-dex linking of interface default-method calls (e.g.
DrawScope), causing IncompatibleClassChangeError.
Without -K, dexes are not re-partitioned (only clinit injection + byte-level
method extraction, both of which preserve class layout), so Compose works fine.

Fix

Skip splitting entirely for any dex that contains "keep-in-place" classes
(currently Landroidx/compose/):

• DexUtils.dexContainsKeepInPlace(File) detects such dexes.
• AndroidPackage.extractDexCode skips splitDex for them; they still go
  through method extraction (matched classes are skipped as before), keeping
  the original class layout intact.
• Dexes without Compose classes are still split, preserving the -K startup
  optimization.
  The prefix list (KEEP_IN_PLACE_PREFIXES) is easy to extend if other
  frameworks hit the same issue.