[FIR JS] Support WRONG_MULTIPLE_INHERITANCE

compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirSession.kt

@@ -74,4 +74,7 @@ class BuiltinTypes {
     val charType: FirImplicitBuiltinTypeRef = FirImplicitCharTypeRef(null)
     val stringType: FirImplicitBuiltinTypeRef = FirImplicitStringTypeRef(null)
     val throwableType: FirImplicitThrowableTypeRef = FirImplicitThrowableTypeRef(null)
+
+    val charSequenceType: FirImplicitCharSequenceTypeRef = FirImplicitCharSequenceTypeRef(null)
+    val charIteratorType: FirImplicitCharIteratorTypeRef = FirImplicitCharIteratorTypeRef(null)
 }

compiler/fir/tree/src/org/jetbrains/kotlin/fir/types/impl/FirImplicitBuiltinTypeRef.kt

@@ -128,6 +128,14 @@ class FirImplicitThrowableTypeRef(
     source: KtSourceElement?
 ) : FirImplicitBuiltinTypeRef(source, StandardClassIds.Throwable)
 
+class FirImplicitCharSequenceTypeRef(
+    source: KtSourceElement?
+) : FirImplicitBuiltinTypeRef(source, StandardClassIds.CharSequence)
+
+class FirImplicitCharIteratorTypeRef(
+    source: KtSourceElement?
+) : FirImplicitBuiltinTypeRef(source, StandardClassIds.CharIterator)
+
 class FirImplicitKPropertyTypeRef(
     source: KtSourceElement?,
     typeArgument: ConeTypeProjection
@@ -199,6 +207,8 @@ fun FirImplicitBuiltinTypeRef.withFakeSource(kind: KtFakeSourceElementKind): Fir
         is FirImplicitCharTypeRef -> FirImplicitCharTypeRef(newSource)
         is FirImplicitStringTypeRef -> FirImplicitStringTypeRef(newSource)
         is FirImplicitThrowableTypeRef -> FirImplicitThrowableTypeRef(newSource)
+        is FirImplicitCharSequenceTypeRef -> FirImplicitCharSequenceTypeRef(newSource)
+        is FirImplicitCharIteratorTypeRef -> FirImplicitCharIteratorTypeRef(newSource)
         is FirImplicitKPropertyTypeRef -> FirImplicitKPropertyTypeRef(
             newSource,
             typeArgument = type.typeArguments[0]