[lldb] Optimized lldb-server memory usage (#100666)

MAX_PATH is definitely larger than 6 bytes we are expecting for this
message, and could be rather large depending on the target OS (4K for
some Linux OSs).

Since the buffer gets allocated on the stack we better be conservative
and allocate what we actually need.

Author: slydiman

lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp

@@ -1145,8 +1145,8 @@ Status GDBRemoteCommunication::StartDebugserverProcess(
       if (socket_pipe.CanWrite())
         socket_pipe.CloseWriteFileDescriptor();
       if (socket_pipe.CanRead()) {
-        char port_cstr[PATH_MAX] = {0};
-        port_cstr[0] = '\0';
+        // The port number may be up to "65535\0".
+        char port_cstr[6] = {0};
         size_t num_bytes = sizeof(port_cstr);
         // Read port from pipe with 10 second timeout.
         error = socket_pipe.ReadWithTimeout(