[compiler] Drop the CompareNilIC.

src/types.h

Index: src/types.h
diff --git a/src/types.h b/src/types.h
index 9984ad8378c9c3814733cfee5f88a26a064c37ea..80614104293bcf568da2fe00b737a2d9f8367358 100644
--- a/src/types.h
+++ b/src/types.h
@@ -42,8 +42,8 @@ namespace internal {
 //   Array < Object
 //   Function < Object
 //   RegExp < Object
-//   Undetectable < Object
-//   Detectable = Receiver \/ Number \/ Name - Undetectable
+//   OtherUndetectable < Object
+//   DetectableReceiver = Receiver - OtherUndetectable
 //
 //   Class(map) < T   iff instance_type(map) < T
 //   Constant(x) < T  iff instance_type(map(x)) < T
@@ -195,8 +195,8 @@ namespace internal {
   V(InternalizedString,  1u << 13 | REPRESENTATION(kTaggedPointer)) \
   V(OtherString,         1u << 14 | REPRESENTATION(kTaggedPointer)) \
   V(Simd,                1u << 15 | REPRESENTATION(kTaggedPointer)) \
-  V(Undetectable,        1u << 16 | REPRESENTATION(kTaggedPointer)) \
   V(OtherObject,         1u << 17 | REPRESENTATION(kTaggedPointer)) \
+  V(OtherUndetectable,   1u << 16 | REPRESENTATION(kTaggedPointer)) \
   V(Proxy,               1u << 18 | REPRESENTATION(kTaggedPointer)) \
   V(Function,            1u << 19 | REPRESENTATION(kTaggedPointer)) \
   V(Internal,            1u << 20 | REPRESENTATION(kTagged | kUntagged)) \
@@ -218,13 +218,13 @@ namespace internal {
   V(BooleanOrNumber,          kBoolean | kNumber) \
   V(BooleanOrNullOrUndefined, kBoolean | kNull | kUndefined) \
   V(NullOrUndefined,          kNull | kUndefined) \
+  V(Undetectable,             kNullOrUndefined | kOtherUndetectable) \
   V(NumberOrString,           kNumber | kString) \
   V(NumberOrUndefined,        kNumber | kUndefined) \
   V(PlainPrimitive,           kNumberOrString | kBoolean | kNullOrUndefined) \
   V(Primitive,                kSymbol | kSimd | kPlainPrimitive) \
   V(DetectableReceiver,       kFunction | kOtherObject | kProxy) \
-  V(Detectable,               kDetectableReceiver | kNumber | kName) \
-  V(Object,                   kFunction | kOtherObject | kUndetectable) \
+  V(Object,                   kFunction | kOtherObject | kOtherUndetectable) \
   V(Receiver,                 kObject | kProxy) \
   V(StringOrReceiver,         kString | kReceiver) \
   V(Unique,                   kBoolean | kUniqueName | kNull | kUndefined | \