[turbofan] Fix optimized lowering of Math.imul.

test/mjsunit/regress/regress-5006.js

Index: test/mjsunit/regress/regress-5006.js
diff --git a/test/mjsunit/regress/regress-3650-3.js b/test/mjsunit/regress/regress-5006.js
similarity index 65%
copy from test/mjsunit/regress/regress-3650-3.js
copy to test/mjsunit/regress/regress-5006.js
index 013e4df2834e20435982300303eb6260eb41b2be..29f145de0ac38c971c0c9174a83ea0cee285bb18 100644
--- a/test/mjsunit/regress/regress-3650-3.js
+++ b/test/mjsunit/regress/regress-5006.js
@@ -4,14 +4,8 @@
 
 // Flags: --allow-natives-syntax
 
-function foo(a) {
-  for (var d in a) {
-    delete a[1];
-  }
-}
-
-foo([1,2,3]);
-foo([2,3,4]);
+function foo(x) { return Math.imul(x|0, 2); }
+print(foo(1));
+print(foo(1));
 %OptimizeFunctionOnNextCall(foo);
-foo([1,2,3]);
-assertOptimized(foo);
+print(foo(1));