[Driver][SYCL] Update header inclusion for source + footer

[mdtoguchi]

Instead of using -internal-isystem for the source location header inclusion,
use -I as a user header, but be sure it is placed after user defined -I
locations.

[AGindinson]

No objections to the change, just curious as to the issues that the previous solution had run into.

[mdtoguchi]

No objections to the change, just curious as to the issues that the previous solution had run into.

Ran into a compilation failure in SYCL_CI with a test where headers weren't being resolved as expected.

[AGindinson]

/summary:run

[AGindinson]

@bader, I believe this PR is safe to merge, since the post-commit failures were Linux-specific, and the current Summary shows no such regressions. Thanks.

[bader]

@bader, I believe this PR is safe to merge, since the post-commit failures were Linux-specific, and the current Summary shows no such regressions. Thanks.

@AGindinson, why do you think this patch can't regress tests on Windows? Was this version of the patch tested on Windows already?

[AGindinson]

@AGindinson, why do you think this patch can't regress tests on Windows? Was this version of the patch tested on Windows already?

Fair point.