Cleanup `isIndex` tests.
Cleanup `isIndex` tests.

Xotic750/lodash,beaugunderson/lodash,Xotic750/lodash,boneskull/lodash,rlugojr/lodash,msmorgan/lodash,boneskull/lodash,steelsojka/lodash,tonyonodi/lodash,steelsojka/lodash,beaugunderson/lodash,msmorgan/lodash,Xotic750/lodash,rlugojr/lodash,tonyonodi/lodash