RFR: 8304069: ClassFileParser has ad-hoc hashtables

[Matias Saavedra Silva]

The ClassFileParser has ad-hoc hash tables for checking for duplicate names for fields, methods and interfaces. ResourceHashtable will now be used instead. Verified with tier1-4 tests.

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

Commit messages:
 - Made hashtable type
 - 8304069: ClassFileParser has ad-hoc hashtables

Changes: https://git.openjdk.org/jdk/pull/13141/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13141&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8304069
  Stats: 90 lines in 1 file changed: 6 ins; 43 del; 41 mod
  Patch: https://git.openjdk.org/jdk/pull/13141.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13141/head:pull/13141

PR: https://git.openjdk.org/jdk/pull/13141