Make Error.prototype.toString spec compliant; and fix various side-effect-free error printing metho…

test/mjsunit/error-tostring.js

Index: test/mjsunit/error-tostring.js
diff --git a/test/mjsunit/error-tostring.js b/test/mjsunit/error-tostring.js
index 8a8a969085124a7d5353431cc9a941b01385c7e7..e4fc6af9db8b6af0ec99b9978d33ac36a2581530 100644
--- a/test/mjsunit/error-tostring.js
+++ b/test/mjsunit/error-tostring.js
@@ -41,7 +41,7 @@ e.message = e;
 e.stack = "Does not occur in output";
 e.arguments = "Does not occur in output";
 e.type = "Does not occur in output";
-assertEquals('', e.toString());
+assertThrows(()=>e.toString(), RangeError);
 
 e = new Error();
 e.name = [ e ];