RFR: 8264873: Dependencies: Split ClassHierarchyWalker [v2]

[Vladimir Ivanov]

> Split ClassHierarchyWalker into ConcreteMethodFinder and ConcreteSubtypeFinder.
> 
> Testing:
> - [x] hs-tier1 - hs-tier4

Vladimir Ivanov has updated the pull request incrementally with one additional commit since the last revision:

  Fix formatting

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3387/files
  - new: https://git.openjdk.java.net/jdk/pull/3387/files/6b905d78..071de4cd

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3387&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3387&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3387.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3387/head:pull/3387

PR: https://git.openjdk.java.net/jdk/pull/3387