RFR: 8339067: Convert Threshold flags (like Tier4MinInvocationThreshold and Tier3MinInvocationThreshold) to double [v3]

[Amit Kumar]

> This is trivial PR to change data type of some "*Threshold" variables form `intx` to `double`.

Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:

  review/comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21354/files
  - new: https://git.openjdk.org/jdk/pull/21354/files/ce4ff580..97d63a29

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21354&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21354&range=01-02

  Stats: 19 lines in 4 files changed: 0 ins; 0 del; 19 mod
  Patch: https://git.openjdk.org/jdk/pull/21354.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21354/head:pull/21354

PR: https://git.openjdk.org/jdk/pull/21354