Elide hole checks on KeyedLoads of holey double arrays.

test/mjsunit/elide-double-hole-check-2.js

Index: test/mjsunit/elide-double-hole-check-2.js
diff --git a/test/mjsunit/regress/regress-crbug-173974.js b/test/mjsunit/elide-double-hole-check-2.js
similarity index 86%
copy from test/mjsunit/regress/regress-crbug-173974.js
copy to test/mjsunit/elide-double-hole-check-2.js
index 905bd6058a0ad0fe2ebe10e4c7dafbe9945cbe3b..978abc3bb0d2861a7afad59c719a16e6738fad92 100644
--- a/test/mjsunit/regress/regress-crbug-173974.js
+++ b/test/mjsunit/elide-double-hole-check-2.js
@@ -27,10 +27,15 @@
 
 // Flags: --allow-natives-syntax
 
-function f() {
-  var count = "";
-  count[0] --;
+function f(a, i) {
+  return a[i] + 0.5;
 }
-f();
+var arr = [0.0,,];
+assertEquals(0.5, f(arr, 0));
+assertEquals(0.5, f(arr, 0));
 %OptimizeFunctionOnNextCall(f);
-f();
+assertEquals(0.5, f(arr, 0));
+assertEquals(NaN, f(arr, 1));
+arr.__proto__ = [1.5,1.5,1.5];
+assertEquals(2, f(arr, 1));
+assertEquals(0.5, f(arr, 0));