RFR: JDK-8309550: jdk.jfr.internal.Utils::formatDataAmount method should graceully handle amounts equal to Long.MIN_VALUE

[Frederic Thevenet]

Please review this simple fix to JDK-8309550.

NB: The problem originally reported only concerned `src/jdk.jfr/share/classes/jdk/jfr/internal/Utils.java`, but since this code was duplicated in `src/jdk.jfr/share/classes/jdk/jfr/internal/util/ValueFormatter.java` with, as far as I understood from the bug description, with an intent to refactor it a a later time, I opted to change both occurrences of the method.

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Commit messages:
 - 8309550: jdk.jfr.internal.Utils::formatDataAmount method should gracefully handle amounts equal to Long.MIN_VALUE

Changes: https://git.openjdk.org/jdk/pull/14341/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14341&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8309550
  Stats: 4 lines in 2 files changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/14341.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14341/head:pull/14341

PR: https://git.openjdk.org/jdk/pull/14341