[jdk11u-dev] RFR: 8168304: Make all of DependencyContext_test available in product mode

[Aleksey Shipilev]

Unclean backport, because there is `find_stale_entries` too.

Additional testing: 
 - [x] Affected test on Linux x86_64 fastdebug
 - [x] Affected test on Linux x86_64 release

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Commit messages:
 - Backport 66c8794c8141632d730a87643e898c6d4951daee

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/96/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=96&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8168304
  Stats: 15 lines in 3 files changed: 2 ins; 5 del; 8 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/96.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/96/head:pull/96

PR: https://git.openjdk.java.net/jdk11u-dev/pull/96