RFR: 8290090: Change CodeBlobType from unscoped enum to enum class

[Axel Boldt-Christmas]

8290090: Change CodeBlobType from unscoped enum to enum class

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

Commit messages:
 - 8290090: Change CodeBlobType from unscoped enum to enum class

Changes: https://git.openjdk.org/jdk/pull/9460/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9460&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290090
  Stats: 78 lines in 11 files changed: 7 ins; 4 del; 67 mod
  Patch: https://git.openjdk.org/jdk/pull/9460.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9460/head:pull/9460

PR: https://git.openjdk.org/jdk/pull/9460