[lldb/testsuite] Change get_debugserver_exe to support Rosetta

In order to be able to run the debugserver tests against the Rosetta
debugserver, detect the Rosetta run configuration and return the
system Rosetta debugserver.

Author: fredriss

lldb/packages/Python/lldbsuite/test/tools/lldb-server/lldbgdbserverutils.py

@@ -12,6 +12,7 @@
 import socket_packet_pump
 import subprocess
 from lldbsuite.test.lldbtest import *
+from lldbsuite.test import configuration
 
 from six.moves import queue
 
@@ -89,6 +90,10 @@ def get_debugserver_exe():
     if "LLDB_DEBUGSERVER_PATH" in os.environ:
         return os.environ["LLDB_DEBUGSERVER_PATH"]
 
+    if configuration.arch and configuration.arch == "x86_64" and \
+       platform.machine().startswith("arm64"):
+        return '/Library/Apple/usr/libexec/oah/debugserver'
+
     return _get_debug_monitor_from_lldb(
         lldbtest_config.lldbExec, "debugserver")