test-dispatch-static-stdlib: drop DispatchStubs

This was used originally for the autorelease elision stub but is no
longer needed. The stubs now simply service the ObjC runtime support,
which is not enabled on Linux. This cleans up the invocation to allow
simplifying the libdispatch build.

Author: compnerd

test-static-stdlib/test-dispatch-static-stdlib.test

@@ -1,7 +1,7 @@
 REQUIRES: platform=Linux
 RUN: rm -rf %t
 RUN: mkdir -p %t
-RUN: %{swiftc} -static-stdlib %S/dispatch_test.swift -ldispatch -lswiftDispatch -lDispatchStubs -o %t/dispatch_test
+RUN: %{swiftc} -static-stdlib %S/dispatch_test.swift -ldispatch -lswiftDispatch -o %t/dispatch_test
 RUN: %t/dispatch_test | %{FileCheck} %s
 
 CHECK: OK