RFR: 8358627: tools/sincechecker/modules/java.base/JavaBaseCheckSince.java fails with JDK 26

[Nizar Benalla]

Once [8346295](https://bugs.openjdk.org/browse/JDK-8346295) is resolved, JavaBaseCheckSince no longer needs to be problemlisted.

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Depends on: https://git.openjdk.org/jdk/pull/25854

Commit messages:
 - this test no longer needs to be problem listed

Changes: https://git.openjdk.org/jdk/pull/25855/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25855&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8358627
  Stats: 6 lines in 1 file changed: 0 ins; 6 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/25855.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25855/head:pull/25855

PR: https://git.openjdk.org/jdk/pull/25855