RFR: 6542: Improve calls to render in the flame view [v2]

[Miroslav Wengner]

> the Flameview shift fix during a fast scrolling over the selections: https://bugs.openjdk.java.net/browse/JMC-6542

Miroslav Wengner has updated the pull request incrementally with one additional commit since the last revision:

  6542: minor changes

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Changes:
  - all: https://git.openjdk.java.net/jmc/pull/133/files
  - new: https://git.openjdk.java.net/jmc/pull/133/files/e1321588..ad0ff6fd

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jmc&pr=133&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jmc&pr=133&range=00-01

  Stats: 7 lines in 1 file changed: 0 ins; 0 del; 7 mod
  Patch: https://git.openjdk.java.net/jmc/pull/133.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/133/head:pull/133

PR: https://git.openjdk.java.net/jmc/pull/133