Refactoring of CompileTimeConstant, introduce flag to represent a constant being referenced by a variable

compiler/testData/cfg/controlStructures/OnlyWhileInFunctionBody.kt

@@ -1,10 +1,10 @@
 fun main() {
-    while(1 > 0) {
+    while(0 > 1) {
       2
     }
 }
 
 fun dowhile() {
     do {return}
-    while(1 > 0)
+    while(0 > 1)
 }