[turbofan] Introduces the SpeculativeNumberShiftLeft opcode.

test/mjsunit/compiler/turbo-number-feedback.js

 // Copyright 2016 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 --turbo-type-feedback
 
 (function AddSubtractSmis() {
   function f0(a, b, c) {
     return a + b - c;
   }
@@ skipping 38 matching lines @@
     }
     return x + b;
   }
 
   assertEquals(1, f3(0, 1));
   assertEquals(1, f3(0, 1));
   %OptimizeFunctionOnNextCall(f3);
   assertEquals(1, f3(0, 1));
   assertEquals(1.5, f3(1, 1));
 })();
+
+(function ShiftLeftSmis() {
+  function f4(a, b) {
+    return a << b;
+  }
+
+  assertEquals(24, f4(3, 3));
+  assertEquals(40, f4(5, 3));
+  %OptimizeFunctionOnNextCall(f4);
+  assertEquals(64, f4(4, 4));
+})();