RFR: 8345403: Add more randomized tests to better cover FloatingDecimal parsing

[Raffaello Giulietti]

`jdk.internal.math.FloatingDecimal` parsing is mostly exercised on inputs produced by `Float.toString` and `Double.toString`, but should be extended on more random inputs.

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Commit messages:
 - Switched to parameterized tests.
 - 8345403: Add more randomized tests to better cover FloatingDecimal parsing

Changes: https://git.openjdk.org/jdk/pull/22523/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22523&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8345403
  Stats: 282 lines in 1 file changed: 282 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/22523.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22523/head:pull/22523

PR: https://git.openjdk.org/jdk/pull/22523