[NI] Improve CST algorithm to handle non-fixed variables

#KT-32456 Fixed
 #KT-32423 Fixed
 #KT-32818 Fixed
 #KT-33197 Fixed

compiler/testData/diagnostics/tests/inference/commonSystem/kt32818.txt

@@ -0,0 +1,4 @@
+package
+
+public val value: kotlin.Int
+public fun </*0*/ T : kotlin.Any> nullable(): T?