AngryPhonebook: uppercased and lowercased are functions so call them

We were not doing any work in this benchmark at -O because we were removing dead
code (to build a tuple of partially applied functions). Now that we are actually
calling the functions we can't eliminate dead code.

This is going to appear as a regression but it is none.

Author: aschwaighofer

benchmark/single-source/AngryPhonebook.swift

@@ -36,7 +36,7 @@ public func run_AngryPhonebook(N: Int) {
   for _ in 1...N {
     for firstname in words {
       for lastname in words {
-        (firstname.uppercased, lastname.lowercased)
+        (firstname.uppercased(), lastname.lowercased())
       }
     }
   }