node.gyp: hard coded include v8.h

[jianchun]

Some recent changes caused hard coded v8.h:

https://github.com/nodejs/node-chakracore/blob/chakracore-master/node.gyp#L209

        'deps/v8/include/v8.h',
        'deps/v8/include/v8-debug.h',

[jianchun]

Please compare with master node.gyp. Some other parts may need sync too. e.g. official v8 deps is now authored as

        [ 'node_use_bundled_v8=="true"', {
          'dependencies': [
            'deps/v8/tools/gyp/v8.gyp:v8',
            'deps/v8/tools/gyp/v8.gyp:v8_libplatform'
          ],
        }],

[kunalspathak]

Some recent changes caused hard coded v8.h:

Seems that it was hard coded from day 1. I will look into it to see what can be done.

[jianchun]

I seem to recall moved them under node_engine=="v8" at some point, maybe change lost long ago.

[kfarnung]

@kunalspathak Can you take a look?