[jdk17u-dev] RFR: 8280868: LineBodyHandlerTest.java creates and discards too many clients

[Goetz Lindenmaier]

I backport this for parity with 17.0.7-oracle.

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Commit messages:
 - Backport 47800bf3da181ae0ee612b14d95773fd1dc90350

Changes: https://git.openjdk.org/jdk17u-dev/pull/1019/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1019&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8280868
  Stats: 23 lines in 1 file changed: 19 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1019.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev pull/1019/head:pull/1019

PR: https://git.openjdk.org/jdk17u-dev/pull/1019