Introduce Variable: Do not delete original expression if its value is used in enclosing expression

idea/testData/refactoring/introduceVariable/IfThenValuedAddBlock.kt

@@ -0,0 +1,3 @@
+fun a(x: Int) {
+    val t = if (x > 0) <selection>x + x</selection> - 1 else x * x + 1
+}

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

@@ -0,0 +1,6 @@
+fun a(x: Int) {
+    val t = if (x > 0) {
+        val i = x + x
+        i - 1
+    } else x * x + 1
+}

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

@@ -3,5 +3,6 @@ fun b() {
     a {it}
     a {
         val i = it
+        i
     }
 }

idea/testData/refactoring/introduceVariable/WhenValuedAddBlock.kt

@@ -0,0 +1,7 @@
+fun a(x: Int) {
+    val t = when {
+        x > 0 -> <selection>x * x</selection> + 1
+        x < 0 -> x + x
+        else -> 0
+    }
+}

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

@@ -0,0 +1,10 @@
+fun a(x: Int) {
+    val t = when {
+        x > 0 -> {
+            val i = x * x
+            i + 1
+        }
+        x < 0 -> x + x
+        else -> 0
+    }
+}