testsuite, gdb.btrace: pass rn-dl-bind.exp with clang

Clang generates slightly different debug information causing
gdb.btrace/rn-dl-bind.exp to fail on its way to the actual test.

Modify the test to remove that dependency.

gdb/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2021-03-03  Markus Metzger  <markus.t.metzger@intel.com>
+
+	* gdb.btrace/rn-dl-bind.exp: Replace reverse-step with
+	reverse-continue to breakpoint.
+
 2021-03-03  Markus Metzger  <markus.t.metzger@intel.com>
 
 	* gdb.btrace/delta.exp: Remove instruction-history and

gdb/testsuite/gdb.btrace/rn-dl-bind.exp

@@ -38,18 +38,28 @@ if ![runto_main] {
 
 # trace the code for the call to test
 gdb_test_no_output "record btrace"
-gdb_test "next" ".*main\.2.*" "next.1"
+gdb_test "next" ".*main\.2.*"
 
 # just dump the function-call-history to help debugging
 gdb_test_no_output "set record function-call-history-size 0"
 gdb_test "record function-call-history /cli 1" ".*"
 
 # check that we can reverse-next and next
-gdb_test "reverse-next" ".*main\.1.*" "reverse-next.1"
-gdb_test "next" ".*main\.2.*" "next.2"
-
-# now go into test and try to reverse-next and next over the library call
-gdb_test "reverse-step" ".*test\.3.*" "reverse-step.1"
-gdb_test "reverse-step" ".*test\.2.*" "reverse-step.2"
-gdb_test "reverse-next" ".*test\.1.*" "reverse-next.2"
-gdb_test "next" ".*test\.2.*" "next.3"
+with_test_prefix "main" {
+    gdb_test "reverse-next" ".*main\.1.*"
+    gdb_test "next" ".*main\.2.*"
+}
+
+# now go into test and try to (reverse-)next over the library call
+#
+# reverse-stepping through the epilogue is not very reliable; depending on
+# debug information we may stop at the closing brace or at the return.
+#
+# instead, run to test
+gdb_breakpoint test {temporary}
+gdb_test "reverse-continue" ".*test\.1.*"
+
+with_test_prefix "test" {
+    gdb_test "next" ".*test\.2.*"
+    gdb_test "reverse-next" ".*test\.1.*"
+}