Support moving into "else" branch of conditional expression

#KT-3877 Fixed

idea/testData/codeInsight/moveUpDown/expressions/intoElse1.kt

@@ -0,0 +1,10 @@
+// MOVE: down
+
+fun foo(x: Boolean) {
+    if (x) {
+        <caret>println(x)
+    }
+    else {
+
+    }
+}

idea/testData/codeInsight/moveUpDown/expressions/intoElse1.kt.after

@@ -0,0 +1,10 @@
+// MOVE: down
+
+fun foo(x: Boolean) {
+    if (x) {
+    }
+    else {
+        <caret>println(x)
+
+    }
+}

idea/testData/codeInsight/moveUpDown/expressions/intoElse2.kt

@@ -0,0 +1,11 @@
+// MOVE: up
+
+fun foo(x: Boolean) {
+    if (x) {
+
+    }
+    else {
+
+    }
+    <caret>println(x)
+}

idea/testData/codeInsight/moveUpDown/expressions/intoElse2.kt.after

@@ -0,0 +1,11 @@
+// MOVE: up
+
+fun foo(x: Boolean) {
+    if (x) {
+
+    }
+    else {
+
+        <caret>println(x)
+    }
+}

idea/testData/codeInsight/moveUpDown/expressions/outOfElse1.kt

@@ -0,0 +1,10 @@
+// MOVE: up
+
+fun foo(x: Boolean) {
+    if (x) {
+
+    }
+    else {
+        <caret>println(x)
+    }
+}

idea/testData/codeInsight/moveUpDown/expressions/outOfElse1.kt.after

@@ -0,0 +1,10 @@
+// MOVE: up
+
+fun foo(x: Boolean) {
+    if (x) {
+
+        <caret>println(x)
+    }
+    else {
+    }
+}

idea/testData/codeInsight/moveUpDown/expressions/outOfElse2.kt

@@ -0,0 +1,10 @@
+// MOVE: down
+
+fun foo(x: Boolean) {
+    if (x) {
+
+    }
+    else {
+        <caret>println(x)
+    }
+}

idea/testData/codeInsight/moveUpDown/expressions/outOfElse2.kt.after

@@ -0,0 +1,10 @@
+// MOVE: down
+
+fun foo(x: Boolean) {
+    if (x) {
+
+    }
+    else {
+    }
+    <caret>println(x)
+}