[turbofan] Extend and make more use of Type::Unique

"t.Is(Type::Unique())" is more conservative and future-proof than
"!t.Maybe(Type::NumericOrString)".

Change-Id: I7d08244802feeb062fd2f8a9d8f3af85eb43bba3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2106207
Commit-Queue: Georg Neis <neis@chromium.org>
Auto-Submit: Georg Neis <neis@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66768}

src/compiler/operation-typer.cc

@@ -1246,9 +1246,7 @@ Type OperationTyper::StrictEqual(Type lhs, Type rhs) {
     DCHECK(lhs.Is(Type::NonInternal()) || lhs.Is(Type::Hole()));
     return singleton_true();
   }
-  if ((!lhs.Maybe(Type::NumericOrString()) ||
-       !rhs.Maybe(Type::NumericOrString())) &&
-      !lhs.Maybe(rhs)) {
+  if ((lhs.Is(Type::Unique()) || rhs.Is(Type::Unique())) && !lhs.Maybe(rhs)) {
     // One of the inputs has a canonical representation but types don't overlap.
     return singleton_false();
   }

src/compiler/types.h

@@ -191,7 +191,7 @@ namespace compiler {
   V(SymbolOrReceiver,             kSymbol | kReceiver) \
   V(StringOrReceiver,             kString | kReceiver) \
   V(Unique,                       kBoolean | kUniqueName | kNull | \
-                                  kUndefined | kReceiver) \
+                                  kUndefined | kHole | kReceiver) \
   V(Internal,                     kHole | kExternalPointer | kOtherInternal) \
   V(NonInternal,                  kPrimitive | kReceiver) \
   V(NonBigInt,                    kNonBigIntPrimitive | kReceiver) \