[jdk8u-dev] RFR: 8266881: Enable debug log for SSLEngineExplorerMatchedSNI.java

[SendaoYan]

Hi all,
  This PR contains two backports [JDK-8266881](https://github.com/openjdk/jdk11u-dev/commit/8138382780b16f4184ad5bbfe07ab2468afe71a8) and [JDK-8227651](https://github.com/openjdk/jdk11u-dev/commit/e8b7e77c8b71946eaee952443e001105b48fe73e) from jdk11u-dev.
We observed `javax/net/ssl/ServerName/SSLEngineExplorerMatchedSNI.java failed intermittently due to SSLException: Tag mismatch` by ours nightly CI, so we want to backport these two PRs to fix the test bugs which cause intermittent fails.

The change in `test/jdk/ProblemList.txt` was not needed deal with in jdk8u-dev, other files are backported cleanly.

Test fix only, the risk is quite low.

Additional testing:

- [ ] full jtreg tests on linux x64
- [ ] full jtreg tests on linux aarch64

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

Commit messages:
 - Backpoer 8138382780b16f4184ad5bbfe07ab2468afe71a8
 - 8266881: Enable debug log for SSLEngineExplorerMatchedSNI.java

Changes: https://git.openjdk.org/jdk8u-dev/pull/567/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=567&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8266881
  Stats: 52 lines in 7 files changed: 5 ins; 4 del; 43 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/567.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/567/head:pull/567

PR: https://git.openjdk.org/jdk8u-dev/pull/567