test/common: Use /index instead of the built /lib/unexpected.
test/common: Use /index instead of the built /lib/unexpected.

This makes regular mocha work, although it currently relies on "common" being asciibetically < "unexpected.spec.js"

Munter/unexpected,bruderstein/unexpected,unexpectedjs/unexpected,alexjeffburke/unexpected,alexjeffburke/unexpected,bruderstein/unexpected