RFR: 8209935: Test to cover CodeSource.getCodeSigners() [v3]

[Sibabrata Sahoo]

> A Test updated to cover the getCodeSigners.

Sibabrata Sahoo has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Merge remote-tracking branch 'upstream/master' into JDK-8209935
 - Update Implies.java
 - Update Implies.java
 - 8209935: Test to cover CodeSource.getCodeSigners()

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8286/files
  - new: https://git.openjdk.java.net/jdk/pull/8286/files/70618a17..c6318862

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8286&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8286&range=01-02

  Stats: 359585 lines in 5089 files changed: 236066 ins; 93423 del; 30096 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8286.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8286/head:pull/8286

PR: https://git.openjdk.java.net/jdk/pull/8286