RFR: 8365983: Tests should throw SkippedException when SCTP not supported [v2]

[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:

  Replace "throw new jtreg.SkippedException" ad "throw new SkippedException"

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Changes:
  - all: https://git.openjdk.org/jdk/pull/26903/files
  - new: https://git.openjdk.org/jdk/pull/26903/files/566b95ee..eb1b137f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26903&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26903&range=00-01

  Stats: 23 lines in 16 files changed: 4 ins; 0 del; 19 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