[jdk17u-dev] RFR: 8328673: Convert closed text/html/CSS manual applet test to main

[Goetz Lindenmaier]

I backport this test change as it also goes to 17.0.17-oracle.

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Commit messages:
 - Backport cd534f8197341fbe3b3811f5be43c88090e16366

Changes: https://git.openjdk.org/jdk17u-dev/pull/3571/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=3571&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8328673
  Stats: 161 lines in 2 files changed: 161 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/3571.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/3571/head:pull/3571

PR: https://git.openjdk.org/jdk17u-dev/pull/3571