Tests: Make availability_weak_linking.swift require enable_target_appletvos

This fixes a test failure when appletvos is not enabled. Also, stop trying to
link against a swift source file. This was causing the linker to emit a scary
warning.

Swift SVN r30158

Author: devincoughlin

test/Interpreter/availability_weak_linking.swift

@@ -1,6 +1,6 @@
 // RUN: rm -rf %t && mkdir -p %t
 // RUN: cp -R %S/Inputs/FakeUnavailableObjCFramework.framework %t
-// RUN: %target-clang -dynamiclib %S/Inputs/FakeUnavailableObjCFramework.m -fmodules %s -F %t -framework Foundation -o %t/FakeUnavailableObjCFramework.framework/FakeUnavailableObjCFramework
+// RUN: %target-clang -dynamiclib %S/Inputs/FakeUnavailableObjCFramework.m -fmodules -F %t -framework Foundation -o %t/FakeUnavailableObjCFramework.framework/FakeUnavailableObjCFramework
 
 // RUN: %target-build-swift -F %t %s -o %t/UseWeaklinkedUnavailableObjCFramework
 
@@ -15,6 +15,7 @@
 
 // REQUIRES: objc_interop
 // REQUIRES: executable_test
+// REQUIRES: enable_target_appletvos
 
 import StdlibUnittest