New setting and test: space around arrow inside 'when'

idea/testData/formatter/WhenArrow.kt

@@ -0,0 +1,8 @@
+fun f(x: Any): Int {
+    return when (x)  {
+        is Int ->1
+        else->0
+    }
+}
+
+// SET_FALSE: SPACE_AROUND_WHEN_ARROW

idea/testData/formatter/WhenArrow_after.kt

@@ -0,0 +1,8 @@
+fun f(x: Any): Int {
+    return when (x) {
+        is Int->1
+        else->0
+    }
+}
+
+// SET_FALSE: SPACE_AROUND_WHEN_ARROW

idea/testData/formatter/WhenArrow_after_inv.kt

@@ -0,0 +1,8 @@
+fun f(x: Any): Int {
+    return when (x) {
+        is Int -> 1
+        else -> 0
+    }
+}
+
+// SET_FALSE: SPACE_AROUND_WHEN_ARROW