Load the configuration settings based on the task's name without assuming "jasmine_node"

It's possible to rename the task using `grunt.renametask`, but if the task is renamed then the settings are not loaded correctly.

This is useful if you want to have multiple test suites which load different configs.

In particular, for my implementation, I want one test suite which runs with `useRequireJs: '...'` for our legacy code, and another with it set to false for our new code, and the only way I can seem to be able to do this is to have two instances of `jasmine_node` running.

*Disclaimer: I'm a bit of a Grunt n00b, so if there's a better way of doing this, then I'd be very glad to know*