Inline function: add extra tests taken from intellij-community

idea/testData/refactoring/inline/function/fromIntellij/SideEffect.kt

@@ -0,0 +1,13 @@
+class Test {
+    private var s: String? = null
+
+    fun <caret>method(): String {
+        s = "Hello"
+        return s
+    }
+
+    fun test() {
+        println(method())
+        println(s)
+    }
+}