Support to build apk odex for both arch.

Build odex for both arch in multilib build if an app has
LOCAL_MULTILIB := both.
Refactored the common setup code to a separate file setup_one_odex.mk.

Bug: 17409149
Bug: 14694978
Change-Id: I74c9426cd74fe0b0cb4811368f740a88ac2ae022
Enable multilib odex only if TARGET_2ND_ARCH is defined.

Bug: 17507247
Bug: 14694978
Change-Id: I160a37bc0970315054606829aa112b67eaee7d49
Merge "Support to build apk odex for both arch."
Merge "Enable multilib odex only if TARGET_2ND_ARCH is defined."