Make test stricter.

One some bots there are additional warnings being printed by LLDB.

rdar://113237769

Author: adrian-prantl

lldb/test/Shell/Swift/MissingVFSOverlay.test

@@ -15,8 +15,5 @@ run
 expression 1
 
 # The {{ }} avoids accidentally matching the input script!
-# CHECK: warning:
-# CHECK-SAME: a.out
-# CHECK: warning:
-# CHECK-SAME: Ignoring missing VFS
-# CHECK-SAME: overlay.yaml
+# CHECK: warning:{{ }}{{.*}}Swift{{.*}}a.out
+# CHECK: warning:{{ }}{{.*}}Ignoring missing VFS{{.*}}overlay.yaml