[lldb] Update header guards to be consistent and compliant with LLVM (NFC)

LLDB has a few different styles of header guards and they're not very
consistent because things get moved around or copy/pasted. This patch
unifies the header guards across LLDB and converts everything to match
LLVM's style.

Differential revision: https://reviews.llvm.org/D74743
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServer.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServer.h
index 86f0abf..93150ff 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServer.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServer.h
@@ -6,8 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef liblldb_GDBRemoteCommunicationServer_h_
-#define liblldb_GDBRemoteCommunicationServer_h_
+#ifndef LLDB_SOURCE_PLUGINS_PROCESS_GDB_REMOTE_GDBREMOTECOMMUNICATIONSERVER_H
+#define LLDB_SOURCE_PLUGINS_PROCESS_GDB_REMOTE_GDBREMOTECOMMUNICATIONSERVER_H
 
 #include <functional>
 #include <map>
@@ -92,4 +92,4 @@
 } // namespace process_gdb_remote
 } // namespace lldb_private
 
-#endif // liblldb_GDBRemoteCommunicationServer_h_
+#endif // LLDB_SOURCE_PLUGINS_PROCESS_GDB_REMOTE_GDBREMOTECOMMUNICATIONSERVER_H