RFR: 6792: Outline shows as not available when starting up with open recording

[Virag Purnam]

Problem: On Re-launch of JMC, previously opened JFR gets loaded and shown in JFR editor. But the outline appears blank. Workaround is to click on the JFR Editor. Please refer the attached files.

![OutlineIsBlank](https://user-images.githubusercontent.com/97600378/151947215-0a445f64-f4f8-43bd-9936-11ddf9ad4f66.jpg)

Fix: On Re-launch of JMC, setting the focus on active JFR editor. This solves the problem and outline gets displayed properly.

![OutlineGetsDisplayed](https://user-images.githubusercontent.com/97600378/151947205-25d9d5dd-5256-4f3f-ba97-327b7ea6b406.jpg)

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Commit messages:
 - 6792: Previously opened JFR remains opened in JMC despite graceful relaunch

Changes: https://git.openjdk.java.net/jmc/pull/373/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jmc&pr=373&range=00
  Issue: https://bugs.openjdk.java.net/browse/JMC-6792
  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jmc/pull/373.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/373/head:pull/373

PR: https://git.openjdk.java.net/jmc/pull/373