Check for validity when accessing call site objects in runtime.

test/mjsunit/regress-crbug-528379.js

Index: test/mjsunit/regress-crbug-528379.js
diff --git a/test/mjsunit/regress/regress-499790.js b/test/mjsunit/regress-crbug-528379.js
similarity index 59%
copy from test/mjsunit/regress/regress-499790.js
copy to test/mjsunit/regress-crbug-528379.js
index ce2cd03f02584387e4a99be230a6d8402893836e..f335f6a104bababf0be733d4c22adb5d694fac8a 100644
--- a/test/mjsunit/regress/regress-499790.js
+++ b/test/mjsunit/regress-crbug-528379.js
@@ -4,11 +4,5 @@
 
 // Flags: --enable-slow-asserts
 
-var a = [1];
-a.foo = "bla";
-delete a.foo;
-a[0] = 1.5;
-
-var a2 = [];
-a2.foo = "bla";
-delete a2.foo;
+Error.prepareStackTrace = function(e, frames) { return frames; }
+assertThrows(function() { new Error().stack[0].getMethodName.call({}); });