[jdk17u-dev] RFR: 8281507: Two javac tests have bad jtreg `@clean` tags

[Goetz Lindenmaier]

I backport this to enable jtreg 7

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Commit messages:
 - Backport 86723d4892485651bcae735ed13545ea89b9bb22

Changes: https://git.openjdk.org/jdk17u-dev/pull/1462/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1462&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8281507
  Stats: 6 lines in 2 files changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1462.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1462/head:pull/1462

PR: https://git.openjdk.org/jdk17u-dev/pull/1462