RFR: 8317132: Prepare HotSpot for permissive- [v5]

[Julian Waters]

> Prepare HotSpot for the permissive- Visual C++ flag, this change contains all of the fixes required for HotSpot to compile under the stricter mode activated when the permissive- flag is passed
> 
> - Reworks code in topLevelUnhandledExceptionFilter for os_windows.cpp to avoid goto jumping across uninitialized locals
> - Adds a CAST_FROM_FN_PTR cast to the return value from ::signal to void, as they cannot be implicitly converted
> - symbolengine.cpp's SimpleBufferWithFallback's templates cannot work with a raw char (Actual fix under discussion)
> - Removed a throw() specification from a mismatched definition in allocation.cpp

Julian Waters has updated the pull request incrementally with one additional commit since the last revision:

  Weird Formatting issue

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15955/files
  - new: https://git.openjdk.org/jdk/pull/15955/files/ac24c014..69009f7e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15955&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15955&range=03-04

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15955.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15955/head:pull/15955

PR: https://git.openjdk.org/jdk/pull/15955