Implement "if null" / "if not null" live templates

idea/testData/templates/ifn.exp.kt

@@ -0,0 +1,16 @@
+val a: String = ""
+val b: String? = ""
+
+class MyClass {
+    val x: String = ""
+    val y: String? = ""
+
+    fun foo() {
+        val s: String = ""
+        val t: String? = ""
+
+        if (b == null) {
+            <caret>
+        }
+    }
+}

idea/testData/templates/ifn.kt

@@ -0,0 +1,14 @@
+val a: String = ""
+val b: String? = ""
+
+class MyClass {
+    val x: String = ""
+    val y: String? = ""
+
+    fun foo() {
+        val s: String = ""
+        val t: String? = ""
+
+        <caret>
+    }
+}

idea/testData/templates/inn.exp.kt

@@ -0,0 +1,16 @@
+val a: String = ""
+val b: String? = ""
+
+class MyClass {
+    val x: String = ""
+    val y: String? = ""
+
+    fun foo() {
+        val s: String = ""
+        val t: String? = ""
+
+        if (b != null) {
+            <caret>
+        }
+    }
+}

idea/testData/templates/inn.kt

@@ -0,0 +1,14 @@
+val a: String = ""
+val b: String? = ""
+
+class MyClass {
+    val x: String = ""
+    val y: String? = ""
+
+    fun foo() {
+        val s: String = ""
+        val t: String? = ""
+
+        <caret>
+    }
+}