RFR: 8287171: Refactor null caller tests to a single directory [v2]

[Tim Prinzing]

> Created a test at test/jdk/jdk/nullCaller called NullCallerTest that creates a test module with some resources in it for the actual tests that occur at the native level. The native part was switched to c++ instead of c to make it easier to create helper objects that reduce the redundant code performing error checking. The two helper classes InstanceCall and StaticCall were placed in an include file called CallHelper.hpp. The main part of the tests are in exeNullCallerTest.cpp, and there is a separate function for each of the bug reports.

Tim Prinzing 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 two additional commits since the last revision:

 - Merge branch 'master' into JDK-8287171
 - 8287171: Refactor null caller tests to a single directory

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8934/files
  - new: https://git.openjdk.java.net/jdk/pull/8934/files/5eba965b..a54aa747

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8934&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8934&range=00-01

  Stats: 2803 lines in 65 files changed: 1631 ins; 617 del; 555 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8934.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8934/head:pull/8934

PR: https://git.openjdk.java.net/jdk/pull/8934