Trim exception stack trace in faults

lib/sandbox.js

@@ -224,13 +224,16 @@ function errorToFault(err) {
   if (!err)
     return null;
 
+  // Trim the stack trace at the self-executing anonymous wrapper function
+  let stackTrimIndex = err.stack.match(/\s+at\s[^\s]+\s+at\s[^\s]+\s\(vm\.js.+\)/).index;
+
   return {
     code: `script.${err.name}`,
     message: err.message,
     detail: {
       name: err.name,
       message: err.message,
-      stack: err.stack
+      stack: err.stack.slice(0, stackTrimIndex)
     }
   }
 }