RFR: 7421: Update Japanese translation for pages

[mohno007]

This PR updates/improves Japanese translation for pages.

Update texts based on new commits to `messages.properties` made after the last update date of the `messages_ja.properties`.

You can see decoded version of `messages_ja` using this script:


native2ascii -reverse application/l10n/org.openjdk.jmc.flightrecorder.ui.ja/src/main/resources/org/openjdk/jmc/flightrecorder/ui/messages/internal/messages_ja.properties

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Commit messages:
 - Update Japanese translation for pages

Changes: https://git.openjdk.java.net/jmc/pull/310/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jmc&pr=310&range=00
  Issue: https://bugs.openjdk.java.net/browse/JMC-7421
  Stats: 73 lines in 1 file changed: 61 ins; 2 del; 10 mod
  Patch: https://git.openjdk.java.net/jmc/pull/310.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/310/head:pull/310

PR: https://git.openjdk.java.net/jmc/pull/310