Fix fuzzer-found error where left and right were the same register in bitops.

src/ia32/virtual-frame-ia32.h

Index: src/ia32/virtual-frame-ia32.h
===================================================================
--- src/ia32/virtual-frame-ia32.h	(revision 5230)
+++ src/ia32/virtual-frame-ia32.h	(working copy)
@@ -139,6 +139,22 @@
     if (is_used(reg)) SpillElementAt(register_location(reg));
   }
 
+  // Make the two registers distinct and spill them.  Returns the second
+  // register.  If the registers were not distinct then it returns the new
+  // second register.
+  Result MakeDistinctAndSpilled(Result* left, Result* right) {
+    Spill(left->reg());
+    Spill(right->reg());
+    if (left->reg().is(right->reg())) {
+      RegisterAllocator* allocator = cgen()->allocator();
+      Result fresh = allocator->Allocate();
+      ASSERT(fresh.is_valid());
+      masm()->mov(fresh.reg(), right->reg());
+      return fresh;
+    }
+    return *right;
+  }
+
   // Spill all occurrences of an arbitrary register if possible.  Return the
   // register spilled or no_reg if it was not possible to free any register
   // (ie, they all have frame-external references).