[jdk25u] RFR: 8365776: Convert JShell tests to use JUnit instead of TestNG

[Ramesh Bhagavatam Gangadhar]

Conflicts in the following files are addressed
==================================
	both modified:   test/langtools/jdk/jshell/ClassesTest.java
	both modified:   test/langtools/jdk/jshell/CompletionSuggestionTest.java
	both modified:   test/langtools/jdk/jshell/InputUITest.java
	both modified:   test/langtools/jdk/jshell/JdiHangingLaunchExecutionControlTest.java
	both modified:   test/langtools/jdk/jshell/JdiHangingListenExecutionControlTest.java
	both modified:   test/langtools/jdk/jshell/ReplToolTesting.java
	both modified:   test/langtools/jdk/jshell/SnippetHighlightTest.java
	deleted by us:   test/langtools/jdk/jshell/ToolCompletionTest.java
	both modified:   test/langtools/jdk/jshell/ToolLocalSimpleTest.java
	both modified:   test/langtools/jdk/jshell/ToolSimpleTest.java
	both modified:   test/langtools/jdk/jshell/VariablesTest.java

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Commit messages:
 - Backport b0ca9bf61e0390a3b022a0915eacabb0cfd92e93

Changes: https://git.openjdk.org/jdk25u/pull/342/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk25u&pr=342&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8365776
  Stats: 1767 lines in 122 files changed: 736 ins; 217 del; 814 mod
  Patch: https://git.openjdk.org/jdk25u/pull/342.diff
  Fetch: git fetch https://git.openjdk.org/jdk25u.git pull/342/head:pull/342

PR: https://git.openjdk.org/jdk25u/pull/342