RFR: JDK-8285756: clean up use of bad arguments for `@clean` in langtools tests

[Jonathan Gibbons]

Please review a trivial test fix to fix some bad/unsupported forms of `@clean` tags in some java tests.

Previously, these bad args were not detected and effectively had no effect.  Now, an upcoming new jtreg version will detect and give errors for these forms.

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Commit messages:
 - JDK-8285756: clean up use of bad arguments for `@clean` in langtools tests

Changes: https://git.openjdk.java.net/jdk/pull/8435/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8435&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8285756
  Stats: 3 lines in 3 files changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8435.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8435/head:pull/8435

PR: https://git.openjdk.java.net/jdk/pull/8435