Fix a bug in my change to ModulesDidLoad in r357955.

In the process of hoisting the LoadScriptingResourceForModule
out of Target::ModuleAdded and into Target::ModulesDidLoad,
I had ModulesDidLoad fetching the Target's entire image list
and look for scripting resources in those -- instead of only
looking for scripting resources in the modules that had
been added to the target's image list.

<rdar://problem/50065315> 

llvm-svn: 358929