ENYO-3815: Reset lastIndex of RegExp between tests on different strings.

Issue
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A dynamic router path will be incorrectly classified as static if the previously added path was a dynamic path.

Fix
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There is a difference in how Chrome (resets to 0 after match), Firefox (does not reset), and IE (does not reset, but has different value than Firefox) handle updating of the `lastIndex` property of a global RegExp. We reset this `lastIndex` property to 0 in-between tests on different paths.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>