src: remove debugger dead code

PR-URL: #12621
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

node.gyp

@@ -159,7 +159,6 @@
         'src/cares_wrap.cc',
         'src/connection_wrap.cc',
         'src/connect_wrap.cc',
-        'src/debug-agent.cc',
         'src/env.cc',
         'src/fs_event_wrap.cc',
         'src/handle_wrap.cc',
@@ -211,7 +210,6 @@
         'src/base-object-inl.h',
         'src/connection_wrap.h',
         'src/connect_wrap.h',
-        'src/debug-agent.h',
         'src/env.h',
         'src/env-inl.h',
         'src/handle_wrap.h',
@@ -612,7 +610,6 @@
         '<(OBJ_PATH)/node_buffer.<(OBJ_SUFFIX)',
         '<(OBJ_PATH)/node_i18n.<(OBJ_SUFFIX)',
         '<(OBJ_PATH)/node_url.<(OBJ_SUFFIX)',
-        '<(OBJ_PATH)/debug-agent.<(OBJ_SUFFIX)',
         '<(OBJ_PATH)/util.<(OBJ_SUFFIX)',
         '<(OBJ_PATH)/string_bytes.<(OBJ_SUFFIX)',
         '<(OBJ_PATH)/string_search.<(OBJ_SUFFIX)',