[FE] Move substitutor related methods to TypeSystemContext

Also use TypeSystemContext instead of TypeSystemInferenceExtensionContext
  in AbstractExpectActualCompatibilityChecker

This is needed to have an ability to implement ExpectActualMatchingContext
  for IR backend. IrTypeSystemContext may operate with type substitutors,
  but there is no sense to implement all methods from TypeSystemInferenceExtensionContext
  in it

core/compiler.common/src/org/jetbrains/kotlin/types/model/TypeSystemContext.kt

@@ -227,12 +227,6 @@ interface TypeSystemInferenceExtensionContext : TypeSystemContext, TypeSystemBui
     fun CapturedTypeMarker.typeParameter(): TypeParameterMarker?
     fun CapturedTypeMarker.withNotNullProjection(): KotlinTypeMarker
 
-    fun typeSubstitutorByTypeConstructor(map: Map<TypeConstructorMarker, KotlinTypeMarker>): TypeSubstitutorMarker
-    fun createEmptySubstitutor(): TypeSubstitutorMarker
-
-    fun TypeSubstitutorMarker.safeSubstitute(type: KotlinTypeMarker): KotlinTypeMarker
-
-
     fun TypeVariableMarker.defaultType(): SimpleTypeMarker
 
     fun createTypeWithAlternativeForIntersectionResult(
@@ -552,6 +546,14 @@ interface TypeSystemContext : TypeSystemOptimizationContext {
     fun substitutionSupertypePolicy(type: SimpleTypeMarker): TypeCheckerState.SupertypesPolicy
 
     fun KotlinTypeMarker.isTypeVariableType(): Boolean
+
+    fun typeSubstitutorByTypeConstructor(map: Map<TypeConstructorMarker, KotlinTypeMarker>): TypeSubstitutorMarker
+    fun createEmptySubstitutor(): TypeSubstitutorMarker
+
+    /**
+     * @returns substituted type or [type] if there were no substitution
+     */
+    fun TypeSubstitutorMarker.safeSubstitute(type: KotlinTypeMarker): KotlinTypeMarker
 }
 
 enum class CaptureStatus {