[Pkg-javascript-devel] rollup 2

[Xavier]

Hi,

rollup 2 seems ready, I rebuilt (+ autopkgtest) all reverse
dependencies. Only some node-rollup-plugin-* legacy tests have to be fixed.
After these fixes, if no one disagree, I'll push rollup 2 to unstable.
This opens the way to have @rollup/plugin-typescript and
@rollup/plugin-buble in unstable. Then, rollup world will be up-to-date
for bullseye.

Main change: rollup depends on itself to build (I didn't succeed to
build it using tsc only). However rollup 1.32.1 succeeds to build rollup
2. I added also a "rebuild-itself" autopkgtest file

Cheers,
Xavier