build: build codecache and snapshot with libnode

[legendecas]

This refactors the node and libnode targets, splitting the node_mksnapshot action from the node exe target, and adding a (always) static node_base target, allowing libnode to depend on node_mksnapshot exe, enabling the node startup snapshot when building with flag --shared.

The new dependency graph would be like:

node (executable)
└── libnode (static or shared)
    ├── node_base (static, whole-archived by `node` when not `--shared`)
    │   ├── node_js2c#host
    │   └── <all C++ sources + js2c generated source>
    ├── node_mksnapshot (executable, build-time)
    │   └── node_base
    └── node_snapshot.cc (generated by `node_mksnapshot`)
        OR node_snapshot_stub.cc

cctest, fuzz_*, embedtest, etc.
└── libnode

[nodejs-github-bot]

Review requested:

• @nodejs/gyp

[joyeecheung]

Thanks. LGTM if CI is happy!

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/73820/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/73832/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/73871/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/73873/

[nodejs-github-bot]

Landed in 3d35dd8