build: remove cctest extension

cctest has `so.59` extension when building node shared library in linux.
The appending is defined in node.gypi and the cctest target in node.gyp
includes node.gypi. Moving the appending from node.gypi to node target
in node.gyp fixes the issue.

Signed-off-by: Yihong Wang <[email protected]>

PR-URL: #16680
Backport-PR-URL: #17258
Reviewed-By: Ben Noordhuis <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Michael Dawson <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Gireesh Punathil <[email protected]>
Reviewed-By: Daniel Bevenius <[email protected]>
Reviewed-By: Refael Ackermann <[email protected]>

node.gypi

@@ -11,11 +11,6 @@
       'defines': [
         'NODE_SHARED_MODE',
       ],
-      'conditions': [
-        [ 'node_module_version!="" and OS!="win"', {
-          'product_extension': '<(shlib_suffix)',
-        }]
-      ],
     }],
     [ 'node_enable_d8=="true"', {
       'dependencies': [ 'deps/v8/src/d8.gyp:d8' ],