Remove interface JavaTypeSubstitutor, use implementation

After 151e55b JavaTypeSubstitutor is only used from inside PSI-based
implementation of Java structure

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/structure/JavaClass.java

@@ -56,9 +56,6 @@ public interface JavaClass extends JavaClassifier, JavaTypeParameterListOwner, J
     @NotNull
     OriginKind getOriginKind();
 
-    @NotNull
-    JavaType createImmediateType(@NotNull JavaTypeSubstitutor substitutor);
-
     enum OriginKind {
         COMPILED,
         SOURCE,

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/structure/JavaClassifierType.java

@@ -27,9 +27,6 @@ public interface JavaClassifierType extends JavaType, JavaAnnotationOwner {
     @Nullable
     JavaClassifier getClassifier();
 
-    @NotNull
-    JavaTypeSubstitutor getSubstitutor();
-
     @NotNull
     @ReadOnly
     Collection<JavaClassifierType> getSupertypes();

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/structure/JavaTypeSubstitutor.java

@@ -1,59 +0,0 @@
-/*
- * Copyright 2010-2015 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.jetbrains.kotlin.load.java.structure;
-
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-
-import java.util.Collections;
-import java.util.Map;
-
-public interface JavaTypeSubstitutor {
-    JavaTypeSubstitutor EMPTY = new JavaTypeSubstitutor() {
-        @NotNull
-        @Override
-        public JavaType substitute(@NotNull JavaType type) {
-            return type;
-        }
-
-        @Nullable
-        @Override
-        public JavaType substitute(@NotNull JavaTypeParameter typeParameter) {
-            return typeParameter.getType();
-        }
-
-        @NotNull
-        @Override
-        public Map<JavaTypeParameter, JavaType> getSubstitutionMap() {
-            return Collections.emptyMap();
-        }
-
-        @Override
-        public String toString() {
-            return "Empty JavaTypeSubstitutor";
-        }
-    };
-
-    @NotNull
-    JavaType substitute(@NotNull JavaType type);
-
-    @Nullable
-    JavaType substitute(@NotNull JavaTypeParameter typeParameter);
-
-    @NotNull
-    Map<JavaTypeParameter, JavaType> getSubstitutionMap();
-}