[jdk17u-dev] RFR: 8294594: Fix cast-function-type warnings in signal handling code

[Aleksey Shipilev]

Need this to unblock MacOS compiler update in GHA.

Partially backports original https://github.com/openjdk/jdk/commit/b06f1b149c8f8a49d4e42c4b782a4b3a22aa79f6. There are lots of conflicts, because:
 1. The original [JDK-8294314](https://bugs.openjdk.org/browse/JDK-8294314) that added more verbose build warnings is not in 17u-dev yet. 
 2. The [JDK-8292054](https://bugs.openjdk.org/browse/JDK-8292054) that added the `/test/hotspot/gtest/runtime/test_signals.cpp` is also not present in 17u-dev.

Additional testing:
 - [x] Linux AArch64 server fastdebug, `all`
 - [x] Linux x86_64 server fastdebug, `all`

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

Commit messages:
 - Backport b06f1b149c8f8a49d4e42c4b782a4b3a22aa79f6

Changes: https://git.openjdk.org/jdk17u-dev/pull/4125/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=4125&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8294594
  Stats: 6 lines in 1 file changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/4125.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/4125/head:pull/4125

PR: https://git.openjdk.org/jdk17u-dev/pull/4125