When you deploy any Apex at all, even one class, all of the test methods in your org will run. Depending on how much Apex you have, how much test data you generate, this could take a long time.

To speed things up, there are some options you have such as reducing your bulk test batch sizes (for instance if you are testing 200 records, try reducing that to 100).

The story behind this is every time when you save a file, mavensmate will trigger the on_post_save() event which will automatically force compile file, which doesn't check whether the file is already compiled or not.

This, I believe, should be a feature request or issue with mavensmate which you can post here. It will be hard for mm to handle too many files at a same time so it should add some logic here to do that via batch. But as you can see, their speed in responding to issues is not very high.

Alternatively, you can write a sublime text plugin to do that. The functionality should be simply, you just need to tell whether the list of files' size is greater than 7 and batch handling it if so.