Copy of issue 155346: Change test status for x64, make test.py pass --arch to Scons.

src/x64/assembler-x64.h

Index: src/x64/assembler-x64.h
===================================================================
--- src/x64/assembler-x64.h	(revision 2455)
+++ src/x64/assembler-x64.h	(working copy)
@@ -718,6 +718,10 @@
     shift_32(dst, 0x4);
   }
 
+  void shll(Register dst, Immediate shift_amount) {
+    shift_32(dst, shift_amount, 0x4);
+  }
+
   void shr(Register dst, Immediate shift_amount) {
     shift(dst, shift_amount, 0x5);
   }