Fix bogus assertion in SetFastDoubleElements.

test/mjsunit/regress/regress-347530.js

Index: test/mjsunit/regress/regress-347530.js
diff --git a/test/mjsunit/regress/regress-crbug-346141.js b/test/mjsunit/regress/regress-347530.js
similarity index 60%
copy from test/mjsunit/regress/regress-crbug-346141.js
copy to test/mjsunit/regress/regress-347530.js
index 798b7704ec2cc0eb928966fdfe9f979d0fe51f94..330fda38c01b5b3c8cc3926fda0520b086aa7289 100644
--- a/test/mjsunit/regress/regress-crbug-346141.js
+++ b/test/mjsunit/regress/regress-347530.js
@@ -2,10 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --harmony-symbols
-
-var s = Symbol()
-var o = {}
-o[s] = 2
-o[""] = 3
-Object.getOwnPropertySymbols(o)
+// Flags: --expose-gc
+a = [];
+a[1000] = .1;
+a.length = 0;
+gc();
+gc();
+a[1000] = .1;
+assertEquals(.1, a[1000]);