FIR deserializer: read nullability & add constructors

compiler/fir/resolve/testData/loadCompiledKotlin/class/javaBean/DifferentGetterAndSetter.txt

@@ -1,6 +1,8 @@
 public open class DifferentGetterAndSetter : R|kotlin/Any| {
     public open fun getSomething(): R|kotlin/Int|
 
-    public open fun setSomething(p0: R|kotlin/String|): R|kotlin/Unit|
+    public open fun setSomething(p0: R|kotlin/String|?): R|kotlin/Unit|
+
+    public constructor()
 
 }

compiler/fir/resolve/testData/loadCompiledKotlin/class/javaBean/JavaBeanVal.txt

@@ -1,4 +1,6 @@
 public open class JavaBeanVal : R|kotlin/Any| {
-    public open fun getColor(): R|kotlin/String|
+    public open fun getColor(): R|kotlin/String|?
+
+    public constructor()
 
 }

compiler/fir/resolve/testData/loadCompiledKotlin/class/javaBean/JavaBeanVar.txt

@@ -1,6 +1,8 @@
 public open class JavaBeanVar : R|kotlin/Any| {
-    public open fun getColor(): R|kotlin/String|
+    public open fun getColor(): R|kotlin/String|?
 
-    public open fun setColor(p0: R|kotlin/String|): R|kotlin/Unit|
+    public open fun setColor(p0: R|kotlin/String|?): R|kotlin/Unit|
+
+    public constructor()
 
 }

compiler/fir/resolve/testData/loadCompiledKotlin/class/javaBean/JavaBeanVarOfGenericType.txt

@@ -1,6 +1,8 @@
 <P> public open class JavaBeanVarOfGenericType : R|kotlin/Any| {
-    public open fun getCharacters(): R|java/util/ArrayList<P>|
+    public open fun getCharacters(): R|java/util/ArrayList<P>|?
 
-    public open fun setCharacters(p0: R|java/util/ArrayList<P>|): R|kotlin/Unit|
+    public open fun setCharacters(p0: R|java/util/ArrayList<P>|?): R|kotlin/Unit|
+
+    public constructor()
 
 }

compiler/fir/resolve/testData/loadCompiledKotlin/class/javaBean/TwoSetters.txt

@@ -1,6 +1,8 @@
 public open class TwoSetters : R|kotlin/Any| {
     public open fun setSize(p0: R|kotlin/Int|): R|kotlin/Unit|
 
-    public open fun setSize(p0: R|kotlin/String|): R|kotlin/Unit|
+    public open fun setSize(p0: R|kotlin/String|?): R|kotlin/Unit|
+
+    public constructor()
 
 }