Retain string characters if add'l argument has spaces

[farisj]

Summary

Consider the instance where you're using optional arguments with yarn run, and one of these arguments is a string that contains spaces. At the moment, using the raw process.argv to obtain these arguments strips the individual arguments of any string separators. Since these arguments are then used in another command, their original intent is lost.

Examples of this problem, as run on the yarn repo itself:

bin/yarn run build -- --module "run | init"
#=> gulp build --module run | init
#=> sh: init: command not found

In the above, the command defined in build interprets | init as a bash command. This is not the intent. "run | init" should be maintained as a single argument.

Test plan

To fix this, this PR sanitizes the optional arguments used in execCommand for the run command. It wraps any argument in " characters if the argument value itself contains a string character.

bin/yarn run build -- --module "run | init"
gulp build --module "run | init"
#=> success!

Not that those arguments would be valid for that command, but one can see that the arguments are passed correctly to whatever internal script is specified.