RFR: JDK-8295859: Update Manual Test Groups [v2]

[Bill Huang]

> This task is created to add manual tests to the manual test groups.
> 
> In addition, fix is provided for TestMatrix.java#Downcall-F and TestMatrix.java#Downcall-T which are failing due to missing TestDowncall.java ([JDK-8287158](https://bugs.openjdk.org/browse/JDK-8287158)).

Bill Huang 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-8295859
 - Updated Manual Test Groups

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Changes:
  - all: https://git.openjdk.org/jdk/pull/10864/files
  - new: https://git.openjdk.org/jdk/pull/10864/files/ec9951c5..2c0bf381

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10864&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10864&range=00-01

  Stats: 151531 lines in 2242 files changed: 50384 ins; 83055 del; 18092 mod
  Patch: https://git.openjdk.org/jdk/pull/10864.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10864/head:pull/10864

PR: https://git.openjdk.org/jdk/pull/10864