Create eggshell function to abort vireo runtime

[rajsite]

There are scenarios in vireo js helpers where assertions should be made that should cause the runtime to abort with an error.

On code paths that are synchronous with executeSlices we can rely on thrown exceptions, however on async callstacks under the user control (JSLI async completion) we cannot throw exceptions to halt the runtime. It would be helpful to have an api function to halt the runtime in those cases. See source.