[jdk21u-dev] RFR: 8340116: test/jdk/sun/security/tools/jarsigner/PreserveRawManifestEntryAndDigest.java can fail due to regex

[Goetz Lindenmaier]

I backport this for parity with 21.0.7-oracle

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Commit messages:
 - Backport 7e87c071b0fd832473f17ec0f579df40bea62950

Changes: https://git.openjdk.org/jdk21u-dev/pull/1261/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1261&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8340116
  Stats: 3 lines in 1 file changed: 0 ins; 2 del; 1 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1261.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1261/head:pull/1261

PR: https://git.openjdk.org/jdk21u-dev/pull/1261