Fix for IDEA complains when assigning Kotlin objects where java.lang.Object is expected

#KT-4355 Fixed

idea/testData/kotlinAndJavaChecker/AssignKotlinClassToObjectInJava.java

@@ -0,0 +1,10 @@
+// KT-4355 IDEA complains when assigning Kotlin objects where java.lang.Object is expected
+class AssignKotlinClassToObjectInJava {
+    void test(KotlinTrait trait) {
+        Object kotlinClass = new KotlinClass();
+        Object kotlinTrait = trait;
+
+        KotlinClass foo = null;
+        foo.equals(foo);
+    }
+}

idea/testData/kotlinAndJavaChecker/AssignKotlinClassToObjectInJava.kt

@@ -0,0 +1,2 @@
+class KotlinClass
+trait KotlinTrait

idea/testData/kotlinAndJavaChecker/AssignMappedKotlinType.java

@@ -0,0 +1,23 @@
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import test.TestPackage;
+
+class AssignMappedKotlinType {
+    void test() {
+        int i1 = TestPackage.getInt();
+        Integer i2 = TestPackage.getInt();
+        Number number = TestPackage.getNumber();
+        String str = TestPackage.getString();
+
+        Collection<Integer> intCollection = TestPackage.getList();
+        List<Integer> intList = TestPackage.getList();
+
+        Collection<Integer> intMutableCollection = TestPackage.getMutableList();
+        List<Integer> intMutableList = TestPackage.getMutableList();
+
+        Collection<String> stringsCollection = TestPackage.getArrayList();
+        ArrayList<String> arrayListCollection = TestPackage.getArrayList();
+    }
+}

idea/testData/kotlinAndJavaChecker/AssignMappedKotlinType.kt

@@ -0,0 +1,11 @@
+package test
+
+import java.util.ArrayList
+
+fun getInt(): Int = 12
+fun getString(): String = "Test"
+fun getNumber(): Number? = null
+
+fun getList(): List<Int> = listOf(1, 2, 3)
+fun getMutableList(): MutableList<Int> = ArrayList<Int>()
+fun getArrayList(): ArrayList<String> = ArrayList<String>()

idea/testData/kotlinAndJavaChecker/UseKotlinSubclassesOfMappedTypes.java

@@ -0,0 +1,6 @@
+class UseKotlinSubclassesOfMappedTypes {
+    void test() {
+        Iterable<String> iterable = new KotlinIterableTraitTest();
+        Comparable<Integer> comparable = new KotlinComparableTest();
+    }
+}

idea/testData/kotlinAndJavaChecker/UseKotlinSubclassesOfMappedTypes.kt

@@ -0,0 +1,11 @@
+class KotlinComparableTest : Comparable<Int> {
+    override fun compareTo(other: Int): Int {
+        throw UnsupportedOperationException()
+    }
+}
+
+class KotlinIterableTraitTest : Iterable<String> {
+    override fun iterator(): Iterator<String> {
+        throw UnsupportedOperationException()
+    }
+}