[turbofan] Always check that we make progress in the Typer.

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index 2430d40e00a5df787f9f1a0b4f737144af17e2ea..0a2c308e3718c1c88236e5df2f3993daf9445a16 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -261,10 +261,10 @@ class Typer::Visitor : public Reducer {
         current = Weaken(node, current, previous);
       }
 
-      DCHECK(previous->Is(current));
+      CHECK(previous->Is(current));
 
       NodeProperties::SetType(node, current);
-      if (!(previous->Is(current) && current->Is(previous))) {
+      if (!current->Is(previous)) {
         // If something changed, revisit all uses.
         return Changed(node);
       }