--tag needs to be set after `getnodeversion` because TAG is defined in
there when DISTTYPE is not "release", setting it before `getnodeversion`
leads to --tag not being passed down in to `configure` and
src/node_version.h setting it as `-pre` by default. This change restores
the functionality that properly sets the TAG for nightlies, rc builds
and other custom build types.

Ref: nodejs/node#17299
Ref: nodejs/abi-stable-node#289

PR-URL: nodejs/node#18031
Ref: nodejs/node#17299
Ref: nodejs/abi-stable-node#289
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: JoãReis <reis@janeasystems.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Kyle Farnung <kfarnung@microsoft.com>