RFR: 8264871: Dependencies: Miscellaneous cleanups in dependencies.cpp

[Vladimir Ivanov]

Miscellaneous cleanups in dependencies.cpp.

Testing:
* [x] hs-tier1 - hs-tier4

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

Commit messages:
 - KlassDepChange::involves_context
 - KlassDepChange::_new_type
 - Dependencies::is_concrete_method
 - Dependencies::verify_method_context
 - int -> uint

Changes: https://git.openjdk.java.net/jdk/pull/3385/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3385&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8264871
  Stats: 156 lines in 2 files changed: 70 ins; 58 del; 28 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3385.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3385/head:pull/3385

PR: https://git.openjdk.java.net/jdk/pull/3385