Refine expression kind definition in postfix templates

- Do not treat if without else as values
- Some statements aren't contained in block (see tests)

 #KT-14107 Fixed
 #KT-14110 Fixed

idea/testData/codeInsight/postfix/soutInIf.kt

@@ -0,0 +1,4 @@
+fun foo(x: Int, y: Int) {
+    if (x > y)
+        x.sout<caret>
+}