build: do not always build the default V8 snapshot

It should be skipped if Node.js is built with the --without-snapshot
configure flag.

PR-URL: https://github.com/nodejs/node/pull/28467
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ujjwal Sharma <usharma1998@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

node.gypi

@@ -70,7 +70,7 @@
     }],
     [ 'node_use_bundled_v8=="true"', {
       'dependencies': [
-        'tools/v8_gypfiles/v8.gyp:v8_snapshot',
+        'tools/v8_gypfiles/v8.gyp:v8_maybe_snapshot',
         'tools/v8_gypfiles/v8.gyp:v8_libplatform',
       ],
     }],