[css-tables-3] Remove file "debug.log"

[nettiwfm]

It was presumably a mistake to add this file to the repository.

The following may be useful to a reviewer:

$ git log -p master -- css-tables-3/debug.log
commit 3ebc8f4adc79064ec074aa1bbb90978eb0d863ae
Author: François REMY <email>
Date:   Tue Jun 20 16:02:35 2017 -0700

    Fix #1025 (colgroup's widths only apply on its columns if their width is auto)

diff --git a/css-tables-3/debug.log b/css-tables-3/debug.log
new file mode 100644
index 000000000..5ae48beca
--- /dev/null
+++ b/css-tables-3/debug.log
@@ -0,0 +1,2 @@
+[0224/101633:ERROR:tcp_listen_socket.cc(76)] Could not bind socket to 127.0.0.1:6004
+[0224/101633:ERROR:node_debugger.cc(86)] Cannot start debugger server