RFR: 8319462: Signature.ClassTypeSig::classDesc() incorrect for inner class types

[Chen Liang]

Observed this erroneous implementation while browsing, and included a quick test against javac output class file to confirm the correct implementation. @asotona Please take a look.

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

Commit messages:
 - 8319462: Signature.ClassTypeSig::classDesc() incorrect for inner class types

Changes: https://git.openjdk.org/jdk/pull/16513/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16513&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8319462
  Stats: 25 lines in 2 files changed: 22 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/16513.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16513/head:pull/16513

PR: https://git.openjdk.org/jdk/pull/16513