RFR: 8357739: [jittester] disable the hashCode method

[Evgeny Nikitin]

JITTester often uses the `hasCode` method (in fact, in almost every generated test). Given that the method can be unstable between runs or in interpreted vs compiled runs, it can create false-positives.

This PR fixes the issue by adding support for method templates similar to the ones used in CompilerCommands). All of those exclude templates match (and exclude) `String.indexOf(String)`, for example:

java/lang/::*(Ljava/lang/String;I)
*String::indexOf(*)
java/lang/*::indexOf


Additionally, the PR adds support for comments (starting from '#') and empty lines in the excludes file.

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

Commit messages:
 - Add unit tests
 - 8357739: [jittester] disable the hashCode method

Changes: https://git.openjdk.org/jdk/pull/25859/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25859&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8357739
  Stats: 556 lines in 4 files changed: 402 ins; 121 del; 33 mod
  Patch: https://git.openjdk.org/jdk/pull/25859.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25859/head:pull/25859

PR: https://git.openjdk.org/jdk/pull/25859