[jdk25u-dev] RFR: 8373632: Some sound tests failing in CI due to lack of sound key

[Roland Mesde]

Backporting JDK-8373632: Some sound tests failing in CI due to lack of sound key.

This PR adds missing sound keyword to 4 jtreg tests that access audio devices, preventing hangs on macOS 26 when run without sound permissions due to a macOS bug.

For parity with Oracle JDK.

Ran related tests on linux-x64, linux-aarch64, macos-aarch64 and windows-x64:

make test TEST=test/jdk/javax/sound/midi/Sequencer/Looping.java
make test TEST=test/jdk/javax/sound/sampled/Clip/IsRunningHang.java
make test TEST=test/jdk/javax/sound/sampled/DataLine/LongFramePosition.java
make test TEST=test/jdk/javax/sound/sampled/DirectAudio/bug6372428.java

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Commit messages:
 - Backport fb531cdaf3b30034e0efa86b9b20558478ce94d0

Changes: https://git.openjdk.org/jdk25u-dev/pull/285/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk25u-dev&pr=285&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8373632
  Stats: 4 lines in 4 files changed: 3 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk25u-dev/pull/285.diff
  Fetch: git fetch https://git.openjdk.org/jdk25u-dev.git pull/285/head:pull/285

PR: https://git.openjdk.org/jdk25u-dev/pull/285