Move spidermonkey17's headers out of LOCALBASE and in there own subdir. [1]

This fixes build issues with other spidermonkey using ports when
SM 1.7 is installed, due to SM 1.7's headers being found first. [2]

Update SM 1.7 users to take this change into account.

PR: 219761 [1], 214724 [2], 202246 [2]
Approved by: maintainer timeout (nearly 2 months)