7903744: Update various versions used by jtreg's IDEA plugin

[liach]

Now that ant is no longer bundled with IDEA, it has to be defined in a different way. And intellij IDEA changed their gradle plugin for IDE plugins so I did a migration to their new gradle plugin, which requires bumping Gradle.

---

Progress

• [ ] Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• [x] Change must not contain extraneous whitespace
• [x] Commit message must refer to an issue

Issue

• CODETOOLS-7903744: Update various versions used by jtreg's IDEA plugin (Enhancement - P4)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jtreg.git pull/201/head:pull/201
$ git checkout pull/201

Update a local copy of the PR:
$ git checkout pull/201
$ git pull https://git.openjdk.org/jtreg.git pull/201/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 201

View PR using the GUI difftool:
$ git pr show -t 201

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jtreg/pull/201.diff

Webrev

Link to Webrev Comment