Speed up bin/webpack* executables by dropping yarn run overhead

[javan]

We were already doing this on Windows only (#584). Just do it.

Before

$ time bin/webpack
yarn run v0.27.5
$ "/Users/javan/Desktop/myapp/node_modules/.bin/webpack" "--config" "/Users/javan/Desktop/myapp/config/webpack/development.js"
Hash: 9a50a6710c2068693890
Version: webpack 3.5.4
Time: 1005ms
         Asset     Size  Chunks                    Chunk Names
hello_react.js  2.05 MB       0  [emitted]  [big]  hello_react
  [82] ./app/javascript/packs/hello_react.jsx 759 bytes {0} [built]
    + 184 hidden modules
Done in 1.77s.

real	0m2.309s
user	0m2.295s
sys	0m0.210s

After

$ time bin/webpack
Hash: 9a50a6710c2068693890
Version: webpack 3.5.4
Time: 958ms
         Asset     Size  Chunks                    Chunk Names
hello_react.js  2.05 MB       0  [emitted]  [big]  hello_react
  [82] ./app/javascript/packs/hello_react.jsx 759 bytes {0} [built]
    + 184 hidden modules

real	0m1.803s
user	0m1.827s
sys	0m0.169s

[dhh]

I thought it wasn't safe to go straight to NODE_MODULES/.bin by yourself?

[gauravtiwari]

@dhh Should be alright however sometimes binaries might get corrupted specially after yarn install (yarnpkg/yarn#1981), probably fixed now. Another thing yarn run does is multiple lookups before bailing out but we are already using the binaries directly on windows so may be do the same for others.

@javan Have you come across this problem when using binaries directly? #364, sometimes the process isn't get killed

[javan]

Executing node_modules/.bin/* is safe and is what yarn run eventually does in our case. yarn run can do additional things like execute "scripts" defined in package.json, but we don't need any of that.

@gauravtiwari, I can't reproduce #364:

Run foreman start

Start a new terminal and run foreman stop, and ps aux | grep webpacker will sometimes show the child process continue in the background.

foreman stop doesn't appear to even be a valid foreman command and stopping foreman "normally" with ctrl+c works as expected.

[dhh]

We don't need foreman anymore now that we're proxing to the dev server.

[gauravtiwari]

@javan Yeah with foreman this isn't a problem but I guess it's happening when we run it directly.