RFR: 8360022: ClassRefDupInConstantPoolTest.java fails when running in repeat

[Chen Liang]

The javac test `ClassRefDupInConstantPoolTest.java` has an incorrect clean directive: when its subsidary Duplicates class is cleaned, the main class is not, and jtreg eagerly reexecutes the main class and then the test fails by not able to find the nested class.

This problem is evident when running from intellij idea. It can also be reproduced consistently by:

make test TEST=langtools/tools/javac/jvm/ClassRefDupInConstantPoolTest.java JTREG=REPEAT_COUNT=2


Testing: that make test line above now passes.

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Commit messages:
 - 8360022: ClassRefDupInConstantPoolTest.java fails when running in repeat

Changes: https://git.openjdk.org/jdk/pull/26106/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26106&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8360022
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/26106.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26106/head:pull/26106

PR: https://git.openjdk.org/jdk/pull/26106