[Coverage] Re-enable coverage smoke test

Author: vedantk

test/SILGen/coverage_smoke.swift

@@ -13,8 +13,6 @@
 // REQUIRES: OS=macosx
 // XFAIL: asan
 
-// REQUIRES: rdar26081474
-
 // CHECK-INTERNAL: Functions shown: 1
 // CHECK-COV: 1|{{.*}}[[@LINE+1]]|{{.*}}func f_internal
 internal func f_internal() {}