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.java

@@ -0,0 +1,8 @@
+public class SomeClass {
+    int a;
+    int b;
+    void doSomeWhile(int i) {
+        while (i < 0)
+            a = b = i;
+    }
+}