Clean up VerifiedMethod.

Remove unused methods, and devirt map.

Results on a large well-known app in speed compile with -j4:

Before:
 dex2oat took [...] native alloc=149MB [...] swap=208MB (218103808B)
After:
 dex2oat took [...] native alloc=84MB [...] swap=208MB (218103808B)

Bug: 34053922
Test: m clean-oat-host && m test-art-host
Change-Id: I0791c1e4ec7a98ae3c98321c582974db8e26617d
3 files changed