RFR: JDK-8297299 SequenceInputStream should not use Vector

[Markus KARG]

There is no need to use a temporary Vector within the constructor of SynchronizedInputStream, as more efficient (non-synchronized) alternative code (like List.of) will do the same in possibly less time. While the optimization is not dramatic, it still makes sense to replace Vector unless synchronization is really needed.

-------------

Commit messages:
 - Replacing Vector by List.of

Changes: https://git.openjdk.org/jdk/pull/11249/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11249&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8297299
  Stats: 8 lines in 1 file changed: 2 ins; 4 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/11249.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11249/head:pull/11249

PR: https://git.openjdk.org/jdk/pull/11249