* Revert "Revert "Share node_modules for samples/js" (#1967)"
This reverts commit 7bb1623e99.
* Add parent directory to the PATH
* Change run-all-js-tests to run samples/js before samples/js/**
* Fix a temporary comment
This is so that we do not need to do npm install 10 times in the
samples directory. Instead we do it once inside samples/js and let
all the sub directories have no dependencies. This works because
nodejs searches the parent directories when looking for a module.
Towards #1888