[jfx21u] RFR: 8313856: Replace VLA with malloc in pango

[Jayathirth D V]

This is backport of https://bugs.openjdk.org/browse/JDK-8313856 to jfx21u.

We should not use stack memory for large VLA allocations in pango.c

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Commit messages:
 - Backport 1752b62320f9e42f6d0d2c1f8278cf2ab205a8f4

Changes: https://git.openjdk.org/jfx21u/pull/8/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx21u&pr=8&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8313856
  Stats: 26 lines in 1 file changed: 22 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jfx21u/pull/8.diff
  Fetch: git fetch https://git.openjdk.org/jfx21u.git pull/8/head:pull/8

PR: https://git.openjdk.org/jfx21u/pull/8