[scan-build-py] Add sarif-html support in scan-build-py

[scan-build-py] Add sarif-html support in scan-build-py

Update scan-build-py to be able to trigger sarif-html output format in clang static analyzer.

NOTE: testcase `test_sarif_and_html_creates_sarif_and_html_reports` will fail if the default clang does not have change https://reviews.llvm.org/D96389 . This can be remediated by pointing the default clang in arguments.py to a locally built clang. I was unable to figure out where these particular tests for scan-build-py are being invoked (aside from manually), so any help there would be greatly appreciated.

Reviewed By: aabbaabb, xazax.hun

Differential Revision: https://reviews.llvm.org/D96570