6.2: [Test] Re-disable test in asserts builds.

The test was reenabled for the `swift_stdlib_asserts` context in
#82559 .  That had the effect of
enabling it for noasserts builds.  But the test uses subpass flags which
are only heeded in asserts builds.  That behavior is disabled--the flags
are made always effective--in
#82736 .  But there's no reason
to take that change onto a release branch.  Just disable the test again
in exactly the relevant configuration.

rdar://154499140

Author: nate-chandler

test/SILOptimizer/semantic-arc-opts-redundantcopyopts.sil

@@ -3,6 +3,9 @@
 // NOTE: Some of our tests here depend on borrow elimination /not/ running!
 // Please do not add it to clean up the IR like we did in
 // semanticarcopts-loadcopy-to-loadborrow!
+//
+// Enabling specific ARC opts requires an asserts build.
+// REQUIRES: asserts
 
 sil_stage canonical