RFR: 8373537: Migrate "test/jdk/com/sun/net/httpserver/" to null-safe "SimpleSSLContext" methods [v2]

[Volkan Yazici]

> Migrates `test/jdk/com/sun/net/httpserver/` to null-safe `SimpleSSLContext` methods introduced in [JDK-8372661], which is a prerequisite for this change set.

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

  Move `SSLContext::setDefault` to static blocks

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Changes:
  - all: https://git.openjdk.org/jdk/pull/28800/files
  - new: https://git.openjdk.org/jdk/pull/28800/files/a6df4b57..c7ef9bd5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28800&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28800&range=00-01

  Stats: 11 lines in 2 files changed: 8 ins; 3 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/28800.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28800/head:pull/28800

PR: https://git.openjdk.org/jdk/pull/28800