RFR: 8313321 : Set minimum python version in WebKit cmake scripts [v3]

[Hima Bindu Meda]

> Minimum version of python ,to run webkit build , on linux is set to 3.6 and for other platforms, minimum version of python is set to 3.8.
> 
> Verified build on all platforms. No issue seen

Hima Bindu Meda has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Merge branch 'master' into python_update
 - change minimum version for mac to 3.6
 - Add check for python version for various platforms

-------------

Changes:
  - all: https://git.openjdk.org/jfx/pull/1205/files
  - new: https://git.openjdk.org/jfx/pull/1205/files/6b73ba2e..6e829316

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1205&range=02
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1205&range=01-02

  Stats: 8102 lines in 161 files changed: 6201 ins; 1035 del; 866 mod
  Patch: https://git.openjdk.org/jfx/pull/1205.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1205/head:pull/1205

PR: https://git.openjdk.org/jfx/pull/1205