[jdk16u] Integrated: 8261022: Fix incorrect result of Math.abs() with char type

[Christoph Langer]

Backport JDK-8261022

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Commit messages:
 - Backport 7a2db858e0e81f2ba17c3554386bb6a833318b3d

Changes: https://git.openjdk.java.net/jdk16u/pull/34/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk16u&pr=34&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8261022
  Stats: 77 lines in 2 files changed: 66 ins; 1 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk16u/pull/34.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk16u pull/34/head:pull/34

PR: https://git.openjdk.java.net/jdk16u/pull/34