Fix C++ type of Factory::NewFixedDoubleArray.

test/mjsunit/regress/regress-empty-fixed-double-array.js

Index: test/mjsunit/regress/regress-empty-fixed-double-array.js
diff --git a/test/mjsunit/regress/regress-observe-map-cache.js b/test/mjsunit/regress/regress-empty-fixed-double-array.js
similarity index 66%
copy from test/mjsunit/regress/regress-observe-map-cache.js
copy to test/mjsunit/regress/regress-empty-fixed-double-array.js
index 4c7a7e3e973d12cde43caaa64b11f6f08cef3dcc..1db9e2b3e54e2abfddddd23f4ee6618ae438db20 100644
--- a/test/mjsunit/regress/regress-observe-map-cache.js
+++ b/test/mjsunit/regress/regress-empty-fixed-double-array.js
@@ -4,11 +4,12 @@
 
 // Flags: --allow-natives-syntax --enable-slow-asserts
 
-function f() {
-  var x = new Array(0);
-  x[-1] = -1;
-  Object.observe(x, function() { });
+function f(a, x) {
+  a.shift();
+  a[0] = x;
 }
 
-f();
-f();
+f([1], 1.1);
+f([1], 1.1);
+%OptimizeFunctionOnNextCall(f);
+f([1], 1.1);