New J2K: separate nullability inference from common one & nullability bug fixes

It will be needed for structure mutability inference

#KT-21467 fixed
#KT-32609 fixed
#KT-32572 fixed
#KT-24677 fixed

idea/idea-test-framework/test/org/jetbrains/kotlin/idea/test/testUtils.kt

@@ -1,17 +1,6 @@
 /*
- * 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.
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.test
@@ -20,6 +9,7 @@ import com.intellij.openapi.editor.Document
 import com.intellij.openapi.project.Project
 import com.intellij.psi.PsiDocumentManager
 import com.intellij.testFramework.LightPlatformTestCase
+import org.jetbrains.kotlin.diagnostics.DiagnosticFactory
 import org.jetbrains.kotlin.diagnostics.Severity
 import org.jetbrains.kotlin.diagnostics.rendering.DefaultErrorMessages
 import org.jetbrains.kotlin.idea.caches.project.LibraryModificationTracker
@@ -29,11 +19,13 @@ import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.test.InTextDirectivesUtils
 import java.util.*
 
-fun KtFile.dumpTextWithErrors(): String {
+fun KtFile.dumpTextWithErrors(ignoreErrors: Set<DiagnosticFactory<*>> = emptySet()): String {
     val text = text
     if (InTextDirectivesUtils.isDirectiveDefined(text, "// DISABLE-ERRORS")) return text
     val diagnostics = analyzeWithContent().diagnostics
-    val errors = diagnostics.filter { it.severity == Severity.ERROR }
+    val errors = diagnostics.filter { diagnostic ->
+        diagnostic.severity == Severity.ERROR && diagnostic.factory !in ignoreErrors
+    }
     if (errors.isEmpty()) return text
     val header = errors.joinToString("\n", postfix = "\n") { "// ERROR: " + DefaultErrorMessages.render(it).replace('\n', ' ') }
     return header + text