RFR: 8232948: javac -h should mangle the overload argument signature

[Joel Borggrén-Franck]

When overloaded methods are disambiguated the appended argument signature
should be mangled according to the spec.

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Commit messages:
 - 8232948: Appease jcheck
 - 8232948: javac -h should mangle the overload argument signature

Changes: https://git.openjdk.java.net/jdk/pull/4345/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4345&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8232948
  Stats: 129 lines in 2 files changed: 121 ins; 0 del; 8 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4345.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4345/head:pull/4345

PR: https://git.openjdk.java.net/jdk/pull/4345