RFR: 8339134: Callers of Exceptions::fthrow should ensure exception message lengths avoid the INT_MAX limits of os::vsnprintf [v2]

[David Holmes]

> This is mostly an audit of the callers of `Exceptions::fthrow` to ensure unbounded strings can't appear.
> 
> There is a code change in DiagnosticCmd parsing to extend the string length limit already used in part of that code.
> 
> Testing:
>  - tier 1-3 (sanity)
> 
> Thanks

David Holmes has updated the pull request incrementally with one additional commit since the last revision:

  Restore previous behaviour for zero length strings

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/21867/files
  - new: https://git.openjdk.org/jdk/pull/21867/files/4ffe35d5..f0e285da

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21867&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21867&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/21867.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21867/head:pull/21867

PR: https://git.openjdk.org/jdk/pull/21867