Fix "Kotlin not configured" issue in common MPP tests.

#KT-27718 Fixed

idea/idea-jps-common/src/org/jetbrains/kotlin/config/KotlinResourceRootType.kt

@@ -7,14 +7,19 @@ package org.jetbrains.kotlin.config
 
 import org.jetbrains.jps.model.ex.JpsElementTypeBase
 import org.jetbrains.jps.model.java.JavaResourceRootProperties
+import org.jetbrains.jps.model.java.JavaResourceRootType
 import org.jetbrains.jps.model.java.JpsJavaExtensionService
 import org.jetbrains.jps.model.module.JpsModuleSourceRootType
 
-sealed class KotlinResourceRootType : JpsElementTypeBase<JavaResourceRootProperties>(),
-        JpsModuleSourceRootType<JavaResourceRootProperties> {
-    object Resource : KotlinResourceRootType()
-    object TestResource : KotlinResourceRootType()
+sealed class KotlinResourceRootType(val isTest: Boolean) : JpsElementTypeBase<JavaResourceRootProperties>(),
+        JpsModuleSourceRootType<JavaResourceRootProperties>, KotlinRootType {
+    object Resource : KotlinResourceRootType(false)
+    object TestResource : KotlinResourceRootType(true)
 
     override fun createDefaultProperties() =
         JpsJavaExtensionService.getInstance().createResourceRootProperties("", false)
+
+    override fun isTestRoot() = isTest
+
+    override fun equals(other: Any?) = if (super.equals(other)) true else isSameRootType(this, other)
 }

idea/idea-jps-common/src/org/jetbrains/kotlin/config/KotlinRootType.kt

@@ -0,0 +1,23 @@
+package org.jetbrains.kotlin.config
+
+import org.jetbrains.jps.model.java.JavaResourceRootType
+import org.jetbrains.jps.model.java.JavaSourceRootType
+
+interface KotlinRootType {
+    fun isTestRoot(): Boolean
+}
+
+//Hack required to fix critical bug KT-27718 it should be removed after support of source root types other than JavaSourceRootType in Idea Core
+fun isSameRootType(kotlinRoot: KotlinRootType, other: Any?): Boolean {
+    if (kotlinRoot.isTestRoot()) {
+        if (other is JavaResourceRootType || other is JavaSourceRootType) {
+            val stack = Thread.currentThread().stackTrace
+            if (stack.size > 2 && "isTestSource" == stack[2].methodName && "com.intellij.openapi.roots.impl.SourceFolderImpl" == stack[2].className) {
+                if (JavaResourceRootType.TEST_RESOURCE == other) {
+                    return true
+                }
+            }
+        }
+    }
+    return false
+}

idea/idea-jps-common/src/org/jetbrains/kotlin/config/KotlinSourceRootType.kt

@@ -7,17 +7,22 @@ package org.jetbrains.kotlin.config
 
 import org.jetbrains.jps.model.ex.JpsElementTypeBase
 import org.jetbrains.jps.model.java.JavaSourceRootProperties
+import org.jetbrains.jps.model.java.JavaSourceRootType
 import org.jetbrains.jps.model.java.JpsJavaExtensionService
 import org.jetbrains.jps.model.module.JpsModuleSourceRootType
 
-sealed class KotlinSourceRootType : JpsElementTypeBase<JavaSourceRootProperties>(), JpsModuleSourceRootType<JavaSourceRootProperties> {
-    object Source : KotlinSourceRootType()
-    object TestSource : KotlinSourceRootType()
+sealed class KotlinSourceRootType(val isTest: Boolean) : JpsElementTypeBase<JavaSourceRootProperties>(), JpsModuleSourceRootType<JavaSourceRootProperties>, KotlinRootType {
+    object Source : KotlinSourceRootType(false)
+    object TestSource : KotlinSourceRootType(true)
 
     override fun createDefaultProperties() = JpsJavaExtensionService.getInstance().createSourceRootProperties("")
 
     companion object {
         val ALL_SOURCES = setOf(Source, TestSource)
     }
+
+    override fun isTestRoot() = isTest
+
+    override fun equals(other: Any?) = if (super.equals(other)) true else isSameRootType(this, other)
 }