[crankshaft] Guard against side effects in Array.prototype.shift lowering.

test/mjsunit/regress/regress-crbug-614644.js

Index: test/mjsunit/regress/regress-crbug-614644.js
diff --git a/test/mjsunit/regress/regress-crbug-624919.js b/test/mjsunit/regress/regress-crbug-614644.js
similarity index 70%
copy from test/mjsunit/regress/regress-crbug-624919.js
copy to test/mjsunit/regress/regress-crbug-614644.js
index 5a2b100daff3dcd5f2d16f253e589baa106f4370..d219cd3b927b035706a2a73a16b936b0324805a3 100644
--- a/test/mjsunit/regress/regress-crbug-624919.js
+++ b/test/mjsunit/regress/regress-crbug-614644.js
@@ -4,11 +4,12 @@
 
 // Flags: --allow-natives-syntax
 
-function f(a, b, c, d, e) {
-  if (a && (b, c ? d() : e())) return 0;
+function f(a, x) {
+  a.shift(2, a.length = 2);
+  a[0] = x;
 }
 
-f();
-f();
+f([ ], 1.1);
+f([1], 1.1);
 %OptimizeFunctionOnNextCall(f);
-f();
+f([1], 1.1);