[jfx21u] Integrated: 8313321: Set minimum python version in WebKit cmake scripts

[Hima Bindu Meda]

Set minimum python version for all platforms.

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Commit messages:
 - Backport bb07bcf7eb60cb772e6d4f135893ff6915c5aa0d

Changes: https://git.openjdk.org/jfx21u/pull/20/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx21u&pr=20&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8313321
  Stats: 18 lines in 1 file changed: 14 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jfx21u/pull/20.diff
  Fetch: git fetch https://git.openjdk.org/jfx21u.git pull/20/head:pull/20

PR: https://git.openjdk.org/jfx21u/pull/20