[jdk17] RFR: JDK-8268774: Residual logging output written to STDOUT, not STDERR

[Jonathan Gibbons]

Please review an interim minimal fix to write logging messages from the javadoc tool to STDERR, not STDOUT.

Recent work focussed on the use of the `Reporter` API in doclets, including the standard doclet. This patch aligns the tool code with the same policies as used in the doclet (and indirectly, in javac.)

Given we're in RDP1, the fix is intentionally minimal. The direct use of JavadocLog.printRawLines is a definite code-smell, and the `notice` methods in `ToolEnvironment` are seemingly obsolete and could be replaced by more appropriate API in `JavadocLog`. JDK-8268831 is a follow-up issue to address these issues.

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

Commit messages:
 - JDK-8268774: Residual logging output written to STDOUT, not STDERR

Changes: https://git.openjdk.java.net/jdk17/pull/68/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk17&pr=68&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268774
  Stats: 131 lines in 5 files changed: 123 ins; 0 del; 8 mod
  Patch: https://git.openjdk.java.net/jdk17/pull/68.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk17 pull/68/head:pull/68

PR: https://git.openjdk.java.net/jdk17/pull/68