Version output may not accurately represent JIT mode

[headius]

The actual run-time JIT mode is not being properly indicated by the version string we produce:

$ jruby -X-C -v                            
jruby 10.0.4.0-SNAPSHOT (3.4.5) 2026-02-10 09e9ecb9de OpenJDK 64-Bit Server VM 21.0.8+9-LTS on 21.0.8+9-LTS +indy +jit [arm64-darwin]

This is due to OutputStrings.getVersionString() basing its output solely on static values like the compiled JRuby version and the JIT mode system property. Whenever possible, it should reflect the JIT mode of the current runtime.