KotlinIntroduceVariableHandler: fix for declarations with expression body

#KT-38449 Fixed

idea/testData/refactoring/introduceVariable/kt38449_int.kt

@@ -0,0 +1,7 @@
+fun b(body: () -> Int) = body()
+
+class A {
+    fun test() = b {
+        <selection>24</selection>
+    }
+}

idea/testData/refactoring/introduceVariable/kt38449_int.kt.after

@@ -0,0 +1,10 @@
+fun b(body: () -> Int) = body()
+
+class A {
+    fun test(): Int {
+        val i = 24
+        return b {
+            i
+        }
+    }
+}

idea/testData/refactoring/introduceVariable/kt38449_unit.kt

@@ -0,0 +1,7 @@
+fun b(body: () -> Unit): Unit = body()
+
+class A {
+    fun test() = b {
+        <selection>24</selection>
+    }
+}

idea/testData/refactoring/introduceVariable/kt38449_unit.kt.after

@@ -0,0 +1,10 @@
+fun b(body: () -> Unit): Unit = body()
+
+class A {
+    fun test() {
+        val i = 24
+        b {
+            i
+        }
+    }
+}