Skip parsing cause if it is not an Error object

* Merges #2013 from @angrycat9000
    * Fixes #2011

src/core/ExceptionFormatter.js

@@ -67,7 +67,7 @@ getJasmineRequireObj().ExceptionFormatter = function(j$) {
         lines.unshift(stackTrace.message);
       }
 
-      if (error.cause) {
+      if (error.cause && error.cause instanceof Error) {
         const substack = this.stack_(error.cause, {
           messageHandling: 'require'
         });