RFR: 8365983: Tests should throw SkippedException when SCTP not supported [v3]

[SendaoYan]

> Currently, take test/jdk/com/sun/nio/sctp/SctpMultiChannel/Branch.java as example. When Util.isSCTPSupported() return false, then test print a warning and the exit.
> 
> I think it's better to throw jtreg.SkippedException rather than only print a warning and then report test passed.
> 
> Change has been verified locally, test-fix only, almost no risk.

SendaoYan has updated the pull request incrementally with one additional commit since the last revision:

  Remove unnecessary "import com.sun.nio.sctp.SctpStandardSocketOptions.InitMaxStreams;"

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Changes:
  - all: https://git.openjdk.org/jdk/pull/26903/files
  - new: https://git.openjdk.org/jdk/pull/26903/files/eb1b137f..11122b91

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26903&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26903&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/26903.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26903/head:pull/26903

PR: https://git.openjdk.org/jdk/pull/26903