Start using ASM6 in jarjar

r.android.com/497292 only started compiling against ASM 6.0, but did
not actually start using ASM6. This change is a manual cherry-pick
of https://github.com/google/jarjar/commit/4b3dcad485871731ef0c9a4f02c055eb5eaa11c2

This is needed as metalava target gets jarjar'ed and now includes
features that require ASM5+

Test: make -j
Change-Id: Ic2d29d0c1ff9cbad282f81a3c9e8ecc5ab6d731a
6 files changed