Fix formatting for when with subjects (KT-27027)

#KT-27027 Fixed

idea/formatter/src/org/jetbrains/kotlin/idea/formatter/kotlinSpacingRules.kt

@@ -236,6 +236,7 @@ fun createSpacingBuilder(settings: CodeStyleSettings, builderUtil: KotlinSpacing
             beforeInside(SECONDARY_CONSTRUCTOR, TokenSet.create(BODY, CLASS_BODY)).lineBreakInCode()
             beforeInside(CLASS, TokenSet.create(BODY, CLASS_BODY)).lineBreakInCode()
             beforeInside(OBJECT_DECLARATION, TokenSet.create(BODY, CLASS_BODY)).lineBreakInCode()
+            beforeInside(PROPERTY, WHEN).spaces(0)
             before(PROPERTY).lineBreakInCode()
 
             after(DOC_COMMENT).lineBreakInCode()

idea/testData/formatter/WhenWithVariable.after.kt

@@ -0,0 +1,29 @@
+fun test() {
+    when (val i = 1) {
+
+    }
+
+    when (var i = 2) {
+
+    }
+
+    when (var i = 2) {
+
+    }
+
+    when (var i = 2
+        ) {
+
+    }
+
+    when (
+        val i = 3) {
+
+    }
+
+    when (
+
+
+        val i = 4) {
+    }
+}

idea/testData/formatter/WhenWithVariable.kt

@@ -0,0 +1,31 @@
+fun test() {
+    when (val i = 1) {
+
+    }
+
+    when (var i = 2) {
+
+    }
+
+    when (    var i = 2     ) {
+
+    }
+
+    when (    var i = 2
+        ) {
+
+    }
+
+    when (
+        val i = 3) {
+
+    }
+
+    when (
+
+
+
+
+        val i = 4) {
+    }
+}

idea/tests/org/jetbrains/kotlin/formatter/FormatterTestGenerated.java

@@ -776,6 +776,11 @@ public class FormatterTestGenerated extends AbstractFormatterTest {
             runTest("idea/testData/formatter/WhenLinesBeforeLbrace.after.kt");
         }
 
+        @TestMetadata("WhenWithVariable.after.kt")
+        public void testWhenWithVariable() throws Exception {
+            runTest("idea/testData/formatter/WhenWithVariable.after.kt");
+        }
+
         @TestMetadata("WhereClause.after.kt")
         public void testWhereClause() throws Exception {
             runTest("idea/testData/formatter/WhereClause.after.kt");