Update the URLs used by dynamic script loading code according to the new
location of the recently-moved web site scripts.

Some JavaScript source files are only relevant in the context of the
Test262 website. They should not be explicitly included by individual
tests, so their presence in the `harness/` directory alongside "include"
files is misleading.

Move the scripts to a location within the `website/` directory to
better-reflect their intended use. Update the relevant HTML templates
with the new locations.