RFR: 8257872: UL: -Xlog does not check number of options

[Koichi Sakata]

In Unified Logging options can be specified up to four (`-Xlog[:[selections][:[output][:[decorators][:output-options]]]]`).
But it’s possible to specify options with more colons like `java -Xlog:::::`.
It’s better to show a message when more options are specified than maximum number.

By this PR a warning message is outputted when options are specified more than the max number.

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Commit messages:
 - Check the number of options in -Xlog

Changes: https://git.openjdk.java.net/jdk/pull/1685/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1685&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8257872
  Stats: 5 lines in 1 file changed: 5 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1685.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1685/head:pull/1685

PR: https://git.openjdk.java.net/jdk/pull/1685