Reclassify test

i536.scala previously compiled since the type argument was inferred to be Nothing.
But that inference is useless; it just hides a runtime failure. The issue scala#536
only complained that the compiler crashed, so having a negative outcome
is permissible.

Author: odersky

tests/pending/pos/i536.scala renamed to tests/neg/i536.scala

@@ -8,5 +8,5 @@ object Max {
   val m1 = max(xs)
   val m2 = max(null)
 
-  java.util.Collections.max(null)
+  java.util.Collections.max(null)  // error: Type argument Comparable[_] does not conform to upper bound Comparable[_ >: LazyRef(Comparable[_])]
 }