[lldb] Remove an outdated comment. NFC.

[mstorsjo]

Summary

This comment became outdated in 053eb35651906e693906fad6c695fce11415ade7
(but was moved along); that commit moved the code and the comment
to a separate function, with a separate local variable
num_of_bytes_read. On error, the possibly garbage value is never
copied back to the caller's reference, thus the comment is no longer
relevant (and slightly confusing as is).

[DavidSpickett]

LGTM

lldb/source/Plugins/Process/Windows/Common/ProcessDebugger.cpp

Status ProcessDebugger::ReadMemory(lldb::addr_t vm_addr, void *buf, size_t size,
   LLDB_LOG(log, "attempting to read {0} bytes from address {1:x}", size,
            vm_addr);
 
   HostProcess process = m_session_data->m_debugger->GetProcess();
   void *addr = reinterpret_cast<void *>(vm_addr);
   SIZE_T num_of_bytes_read = 0;
   if (!::ReadProcessMemory(process.GetNativeProcess().GetSystemHandle(), addr,
                            buf, size, &num_of_bytes_read)) {
-    // Reading from the process can fail for a number of reasons - set the
-    // error code and make sure that the number of bytes read is set back to 0
-    // because in some scenarios the value of bytes_read returned from the API
-    // is garbage.
     error.SetError(GetLastError(), eErrorTypeWin32);
     LLDB_LOG(log, "reading failed with error: {0}", error);
   } else {
     bytes_read = num_of_bytes_read;
   }
   return error;
 }