KT-3174 Call resolver doesn't understand type is not-nullable after ?. safe call

#KT-3174 fixed

compiler/testData/diagnostics/tests/inference/regressions/kt3174.kt

@@ -0,0 +1,12 @@
+//KT-3174 Call resolver doesn't understand type is not-nullable after ?. safe call
+package a
+
+fun <T: Any> T.test(): T = this
+fun foo(a: Any?) = a?.test() // Error
+
+fun <T> T.fff(l: MutableList<T>) = l.add(this)
+
+fun test(s: String?, l: MutableList<String>) {
+    s?.fff(l)
+
+}