RFR: 8292494: Ensure SystemDictionary::set_platform_loader and set_system_loader are called only once

[David Holmes]

On Tue, 23 Aug 2022 18:24:30 GMT, Calvin Cheung <ccheung at openjdk.org> wrote:

> The `SystemDictionary::set_platform_loader` and the `SystemDictionary::set_system_loader` functions should only be called once during VM startup, this simple fix ensures that.
> 
> Passed mach5 tiers 1,2,3 testing.

Looks good!

Thanks

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

Marked as reviewed by dholmes (Reviewer).

PR: https://git.openjdk.org/jdk/pull/9988