Set clobbers_flags to False for urm_noflags_abcd.

`urm_noflags` is a variant of `urm` which doesn't clobber the flags, and
`urm_noflags_abcd` is a further variant for ABCD registers, so it also
doesn't clobber the flags.

lib/filetests/src/lib.rs

@@ -45,6 +45,7 @@ mod test_postopt;
 mod test_preopt;
 mod test_print_cfg;
 mod test_regalloc;
+mod test_shrink;
 mod test_simple_gvn;
 mod test_verifier;
 
@@ -92,6 +93,7 @@ fn new_subtest(parsed: &TestCommand) -> subtest::SubtestResult<Box<subtest::SubT
         "preopt" => test_preopt::subtest(parsed),
         "print-cfg" => test_print_cfg::subtest(parsed),
         "regalloc" => test_regalloc::subtest(parsed),
+        "shrink" => test_shrink::subtest(parsed),
         "simple-gvn" => test_simple_gvn::subtest(parsed),
         "verifier" => test_verifier::subtest(parsed),
         _ => Err(format!("unknown test command '{}'", parsed.command)),