Improve string layout in dexlayout.

Adds more strings to what dexlayout considers hot:
  - A profiled class's superclass and interface class names
  - The class names of accessed fields
  - The class name, name, and shorty of methods accessed by clinits

TODO: Gather memory numbers

Bug: 35800981
Test: mm test-art-host
Change-Id: I1a7de5bd5b1b73559624af939de05a2111f78195