tests: add more tests for "hg shelve --delete"
It appears that the only tests for "hg shelve --delete" concern command
errors (e.g. incompatible command options). Adding some more to check
that non-existent names are handled and a success case.
Differential Revision: https://phab.mercurial-scm.org/D7460
{
// Enforcing
"eqeqeq" : true, // true: Require triple equals (===) for comparison
"forin" : true, // true: Require filtering for..in loops with obj.hasOwnProperty()
"freeze" : true, // true: prohibits overwriting prototypes of native objects such as Array, Date etc.
"nonbsp" : true, // true: Prohibit "non-breaking whitespace" characters.
"undef" : true, // true: Require all non-global variables to be declared (prevents global leaks)
// Environments
"browser" : true // Web Browser (window, document, etc)
}