Fix HashTable growth strategy to be 2x instead of 4x

test/mjsunit/ensure-growing-store-learns.js

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --allow-natives-syntax --noverify-heap --noenable-slow-asserts
 // Flags: --crankshaft --no-always-opt
 
 // --noverify-heap and --noenable-slow-asserts are set because the test is too
 // slow with it on.
 
@@ skipping 47 matching lines @@
   foo2(a, 10);
   foo2(a, 12);
   foo2(a, 31);
   %OptimizeFunctionOnNextCall(foo2);
   foo2(a, 40);
 
   assertOptimized(foo2);
   assertTrue(%HasFastSmiElements(a));
 
   // Grow a large array into large object space through the keyed store
-  // without deoptimizing. Grow by 10s. If we set elements too sparsely, the
+  // without deoptimizing. Grow by 9s. If we set elements too sparsely, the
   // array will convert to dictionary mode.
   a = new Array(99999);
   assertTrue(%HasFastSmiElements(a));
-  for (var i = 0; i < 263000; i += 10) {
+  for (var i = 0; i < 263000; i += 9) {
     foo2(a, i);
   }
 
   // Verify that we are over 1 page in size, and foo2 remains optimized.
   // This means we've smoothly transitioned to allocating in large object
   // space.
   assertTrue(%HasFastSmiElements(a));
   assertTrue(a.length * 4 > (1024 * 1024));
   assertOptimized(foo2);
 
   %ClearFunctionFeedback(foo2);
 })();