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/doWhileStatement/whileWithAssignmentAsExpression.java

@@ -0,0 +1,7 @@
+public class SomeClass {
+    int a;
+    int b;
+    void doSomeWhile(int i) {
+        do a = b = i; while (i < 0)
+    }
+}