Revert "Revert "[analyzer] Teach scan-build how to rebuild index.html without analyzing.""
This reverts commit 21efb06f0ae2eb999f566d989997256d6cb12206.
Changes since last attempt to land this patch:
- Sort files before deduplicating. This hopefully avoids some buildbot failures.
- Fix use of uninitialized variable when running without --use-analyzer.
- Remove the "REQUIRES: windows" item.