Tighter control of stripping in dex_preopt_odex_install.

- Move logic to uncompress dexs in an APK in dex_preopt_odex_install.mk
  and definitions.mk.
- Explicitly mark nostripping cases where dexpreopt will not embed the dex
  file in the APK.

bug: 63920015
Test: m
Test: verify priv-apps dexs are uncompressed and unstripped
Test: Verify a non priv-app APK with uncompressed dex doesn't get stripped.

Change-Id: I624a03e3d965cebc0cae43fd6f7a6260178e6b8a