RFR: 8273610: LogTestFixture::restore_config() should not restore options

[Ioi Lam]

This is a prerequisite of https://github.com/openjdk/jdk/pull/5407

LogTestFixture::restore_config() should not restore the options because it's neither necessary nor allowed. Please see the RFE description for details.

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Commit messages:
 - 8273610: LogTestFixture::restore_config() should not restore options

Changes: https://git.openjdk.java.net/jdk/pull/5472/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5472&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273610
  Stats: 9 lines in 1 file changed: 4 ins; 3 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5472.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5472/head:pull/5472

PR: https://git.openjdk.java.net/jdk/pull/5472