New J2K: make post-processing aware of other files which are being converted

Before post-processing was able to handle only one converting file at once
So, some conversions (like (field, getter, setter) to Kotlin property)
was not able to work when converting class hierarchy was split into
multiple files.
Also, inferring nullability for a set of files was broken

#KT-19569 fixed
#KT-34266 fixed
#KT-32518 fixed

nj2k/testData/multiFile/DetectPropertiesMultipleFiles/B.java

@@ -0,0 +1,31 @@
+package test;
+
+public class B {
+    public String getFromB1() {
+        return "";
+    }
+
+    public String getFromB2() {
+        return "";
+    }
+
+    public void setFromB2(String value) {
+    }
+
+    public String getFromB3() {
+        return "";
+    }
+
+    public void setFromB3(String value) {
+    }
+
+    public String getFromB4() {
+        return "";
+    }
+
+    public void setFromB4(String value) {
+    }
+
+    public void setFromB5(String value) {
+    }
+}

nj2k/testData/multiFile/DetectPropertiesMultipleFiles/B.kt

@@ -0,0 +1,20 @@
+package test
+
+open class B {
+    val fromB1: String
+        get() = ""
+
+    var fromB2: String?
+        get() = ""
+        set(value) {}
+
+    var fromB3: String?
+        get() = ""
+        set(value) {}
+
+    var fromB4: String?
+        get() = ""
+        set(value) {}
+
+    open fun setFromB5(value: String?) {}
+}

nj2k/testData/multiFile/DetectPropertiesMultipleFiles/C.java

@@ -0,0 +1,57 @@
+package test;
+
+public abstract class C extends B implements I {
+    private final int mySomething1;
+    private int mySomething6;
+
+    C(int something1) {
+        mySomething1 = something1;
+    }
+
+    @Override
+    public int getSomething1() {
+        return mySomething1;
+    }
+
+    @Override
+    public int getSomething2() {
+        return 0;
+    }
+
+    @Override
+    public int getSomething3() {
+        return 0;
+    }
+
+    @Override
+    public void setSomething3(int value) {
+    }
+
+    @Override
+    public int getSomething4() {
+        return 0;
+    }
+
+    @Override
+    public void setSomething5(int value) {
+
+    }
+
+    public int getSomething6() {
+        return mySomething6;
+    }
+
+    @Override
+    public void setSomething6(int value) {
+        mySomething6 = value;
+    }
+
+    public String getFromB5() {
+        return "";
+    }
+
+    @Override
+    public void setFromB5(String value) {
+        super.setFromB5(value);
+    }
+}

nj2k/testData/multiFile/DetectPropertiesMultipleFiles/C.kt

@@ -0,0 +1,34 @@
+package test
+
+abstract class C internal constructor(override val something1: Int) : B(), I {
+    private var mySomething6 = 0
+
+    override val something2: Int
+        get() = 0
+
+    override var something3: Int
+        get() = 0
+        set(value) {}
+
+    override fun getSomething4(): Int {
+        return 0
+    }
+
+    override fun setSomething5(value: Int) {}
+    fun getSomething6(): Int {
+        return mySomething6
+    }
+
+    override fun setSomething6(value: Int) {
+        mySomething6 = value
+    }
+
+    fun getFromB5(): String {
+        return ""
+    }
+
+    override fun setFromB5(value: String?) {
+        super.setFromB5(value)
+    }
+
+}

nj2k/testData/multiFile/DetectPropertiesMultipleFiles/I.java

@@ -0,0 +1,21 @@
+package test;
+
+public interface I {
+    int getSomething1();
+
+    int getSomething2();
+
+    int getSomething3();
+
+    void setSomething3(int value);
+
+    int getSomething4();
+
+    void setSomething4(int value);
+
+    int getSomething5();
+
+    void setSomething5(int value);
+
+    void setSomething6(int value);
+}

nj2k/testData/multiFile/DetectPropertiesMultipleFiles/I.kt

@@ -0,0 +1,13 @@
+package test
+
+interface I {
+    val something1: Int
+    val something2: Int
+    var something3: Int
+
+    fun getSomething4(): Int
+    fun setSomething4(value: Int)
+    fun getSomething5(): Int
+    fun setSomething5(value: Int)
+    fun setSomething6(value: Int)
+}

nj2k/testData/multiFile/DetectPropertiesMultipleFiles/I1.java

@@ -0,0 +1,7 @@
+package test;
+
+public interface I1 extends I {
+    void setSomething1(int value);
+
+    int getSomething6();
+}

nj2k/testData/multiFile/DetectPropertiesMultipleFiles/I1.kt

@@ -0,0 +1,6 @@
+package test
+
+interface I1 : I {
+    fun setSomething1(value: Int)
+    val something6: Int
+}