[lldb][AIX] Host.cpp for AIX (#130582)

This PR is in reference to porting LLDB on AIX.

Link to discussions on llvm discourse and github:

1. https://discourse.llvm.org/t/port-lldb-to-ibm-aix/80640
2. #101657
The complete changes for porting are present in this draft PR:
#102601

Added base file - aix/Host.cpp for Process info

Author: DhruvSrivastavaX

lldb/source/Host/CMakeLists.txt

@@ -135,6 +135,7 @@ else()
 
   elseif (CMAKE_SYSTEM_NAME MATCHES "AIX")
     add_host_subdirectory(aix
+      aix/Host.cpp
       aix/HostInfoAIX.cpp
       )
   endif()

lldb/source/Host/aix/Host.cpp

@@ -0,0 +1,25 @@
+//===-- source/Host/aix/Host.cpp ----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Host/Host.h"
+#include "lldb/Utility/Status.h"
+
+using namespace lldb_private;
+
+uint32_t Host::FindProcessesImpl(const ProcessInstanceInfoMatch &match_info,
+                                 ProcessInstanceInfoList &process_infos) {
+  return 0;
+}
+
+bool Host::GetProcessInfo(lldb::pid_t pid, ProcessInstanceInfo &process_info) {
+  return false;
+}
+
+Status Host::ShellExpandArguments(ProcessLaunchInfo &launch_info) {
+  return Status("unimplemented");
+}