Fixes https://github.com/denoland/deno/issues/24749
Runs a server that just returns the header tarball and checksum, and
sets the `NODEJS_ORG_MIRROR` env var so that `node-gyp` uses it instead
of `nodejs.org`
This looks like a massive PR, but it's only a move from cli/tests ->
tests, and updates of relative paths for files.
This is the first step towards aggregate all of the integration test
files under tests/, which will lead to a set of integration tests that
can run without the CLI binary being built.
While we could leave these tests under `cli`, it would require us to
keep a more complex directory structure for the various test runners. In
addition, we have a lot of complexity to ignore various test files in
the `cli` project itself (cargo publish exclusion rules, autotests =
false, etc).
And finally, the `tests/` folder will eventually house the `test_ffi`,
`test_napi` and other testing code, reducing the size of the root repo
directory.
For easier review, the extremely large and noisy "move" is in the first
commit (with no changes -- just a move), while the remainder of the
changes to actual files is in the second commit.
