Libcore: Expose compilation filter in DexFile

To allow checking the state of a dex file wrt/ compilation modes,
expose methods to check compiler filter strings and extend the
signature of getDexOptNeeded.

Bug: 27689078

(cherry picked from commit 643e8cb87528bb6479eb7f25120fc11de3e4a9b3)

Change-Id: I06b9d75f58c59cb07ef5170f784ea6745168efaa
1 file changed