RFR: 8313856: Replace VLA with malloc in pango

[Jayathirth D V]

We should not use stack for array memory allocations in JNI.
Updated pango.c to use malloc for arrays and release them at appropriate places.

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Commit messages:
 - 8313856: Replace VLA with malloc in pango

Changes: https://git.openjdk.org/jfx/pull/1202/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1202&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/jfx/pull/1202.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1202/head:pull/1202

PR: https://git.openjdk.org/jfx/pull/1202