[vm/ffi] `CCallInstr` fix product mode

Don't refer to `RepresentationToCString` in product mode.

TEST=product build of SDK

Change-Id: I1356934da926ec910c5d78980b64c9f42b8a60f3
Cq-Include-Trybots: luci.dart.try:app-kernel-linux-product-x64-try,vm-kernel-precomp-mac-product-x64-try,vm-kernel-precomp-linux-product-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/246500
Commit-Queue: Aske Simon Christensen <askesc@google.com>
Auto-Submit: Daco Harkes <dacoharkes@google.com>
Reviewed-by: Aske Simon Christensen <askesc@google.com>
Commit-Queue: Daco Harkes <dacoharkes@google.com>
diff --git a/runtime/vm/compiler/backend/il.cc b/runtime/vm/compiler/backend/il.cc
index 8e50cc3..e4ba8ff 100644
--- a/runtime/vm/compiler/backend/il.cc
+++ b/runtime/vm/compiler/backend/il.cc
@@ -7056,9 +7056,11 @@
     } else if (argument_location.IsStack()) {
       const Location src_loc = rebase.Rebase(locs()->in(i));
       const Representation src_rep = RequiredInputRepresentation(i);
+#if defined(INCLUDE_IL_PRINTER)
       __ Comment("Param %" Pd ": %s %s -> %s", i, src_loc.ToCString(),
                  RepresentationToCString(src_rep),
                  argument_location.ToCString());
+#endif
       compiler->EmitMoveToNative(argument_location, src_loc, src_rep,
                                  &temp_alloc);
     } else {