Implement << operator for DexRegisterLocation::Kind.

This makes it comparable in DCHECK_EQ and similar methods.

Change-Id: I6b5b237be89325850ae6860d011fd6741189ab01
diff --git a/runtime/jit/jit.cc b/runtime/jit/jit.cc
index 8d3da37..c6ec5b0 100644
--- a/runtime/jit/jit.cc
+++ b/runtime/jit/jit.cc
@@ -378,8 +378,7 @@
           continue;
         }
 
-        DCHECK(location == DexRegisterLocation::Kind::kInStack)
-            << DexRegisterLocation::PrettyDescriptor(location);
+        DCHECK_EQ(location, DexRegisterLocation::Kind::kInStack);
 
         int32_t vreg_value = shadow_frame->GetVReg(vreg);
         int32_t slot_offset = vreg_map.GetStackOffsetInBytes(vreg,