Fix conversion of assignment as expression in J2K

Blockless if's and so with assignment as expression inside
should turn into blockful
 #KT-16816 fixed

j2k/testData/fileOrElement/whileStatement/whileWithAssignmentAsExpression.kt

@@ -0,0 +1,10 @@
+class SomeClass {
+    internal var a: Int = 0
+    internal var b: Int = 0
+    internal fun doSomeWhile(i: Int) {
+        while (i < 0) {
+            b = i
+            a = b
+        }
+    }
+}