[jdk21u-dev] RFR: 8342934: TYPE_USE annotations printed with error causing "," in toString output

[Liam Miller-Cushon]

This backport of [JDK-8342934](https://bugs.openjdk.org/browse/JDK-8342934) fixes a bug in `TypeMirror#toString` output.

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Commit messages:
 - Backport ff165f9f0cf519144d7361b766bcce53d04c518e

Changes: https://git.openjdk.org/jdk21u-dev/pull/1802/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1802&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8342934
  Stats: 8 lines in 3 files changed: 4 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1802.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1802/head:pull/1802

PR: https://git.openjdk.org/jdk21u-dev/pull/1802