ATS plugins are too tolerant of loading bad configs

[traeak]

With ATS plugins like header rewrite the loaders themselves are very tolerant of errors inside the config files themselves, typically only blocking ATS starts and reloads when config files are missing. This is done by returning TS_ERROR from TSRemapNewInstance.

Example of header rewrite that should block reload:

# mistype of condition:
cond %{PSEUDO__REMAP_HOOK}

This might require further investigation of what might be required.

[cmcfarlen]

@zwoop noticed this as well. This is an issue with some plugins not returning an error on init when they have bad config, even if they print an error.

We should probably identify the plugins that aren't returning errors and fix those. @zwoop might already have a list!