ART: Cache sections for sanity check

Cache image sections for ArtMethod image sanity checks. Reduces
executed instructions in debug builds.

$ perf stat -e instructions:u -B dex2oatd ... HelloWorld.dex
Before: 36,024,262,237      instructions:u
After:  20,351,917,735      instructions:u

Test: m test-art-host
Change-Id: I96e5c04483cf40800f0f336a49d7d33e7b967f07