[code-reflection] Integrated: config now accessible from all backends

[Gary Frost]

Config now setup for all backends. 

This allows us to test capabilities (such as SHOW_CODE) in all backends

We should lean on this rather than Boolean.get(propName).

-------------

Commit messages:
 - config now accessible from all backends

Changes: https://git.openjdk.org/babylon/pull/597/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=597&range=00
  Stats: 290 lines in 30 files changed: 153 ins; 52 del; 85 mod
  Patch: https://git.openjdk.org/babylon/pull/597.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/597/head:pull/597

PR: https://git.openjdk.org/babylon/pull/597