Retain data flow info after binary calls

Make autocasts in CandidateResolver when checking value argument types

 #KT-2825 In Progress

compiler/testData/diagnostics/tests/dataFlowInfoTraversal/BinaryExpressionPlusConvention.kt

@@ -0,0 +1,16 @@
+trait A
+
+trait B : A
+fun B.plus(b: B) = if (this == b) b else this
+
+fun foo(a: A): B {
+    val result = (a as B) + a
+    a : B
+    return result
+}
+
+fun bar(a: A, b: B): B {
+    val result = b + (a as B)
+    a : B
+    return result
+}