tests/sigtramp_test: xfail on non-amd64

This test fail until at least https://reviews.llvm.org/D155066 is
rebased and picked up for aarch64 and more work is done for the other
archs.

PR:		289096
Reviewed by:	jlduran
Fixes:		fef84fd8ae
MFC after:	3 days

lib/libexecinfo/tests/sigtramp_test.c

@@ -45,12 +45,12 @@ handler(int signum __unused)
 ATF_TC_WITHOUT_HEAD(test_backtrace_sigtramp);
 ATF_TC_BODY(test_backtrace_sigtramp, tc)
 {
-#if defined(__aarch64__)
+#if !defined(__amd64__)
 	/*
 	 * https://reviews.llvm.org is deprecated and
 	 * this review is never going to be updated or completed
 	 */
-	atf_tc_expect_fail("https://reviews.llvm.org/D155066");
+	atf_tc_expect_fail("https://reviews.llvm.org/D155066 and https://bugs.freebsd.org/289096");
 #endif
 
 	struct sigaction act;