Fix integer overflow, implicit integer sign change and truncation

Fix integer overflow in cabac psy-trellis and cavcl trellis.

And other implicit integer sign change and truncation reported by clang's UBSan: -fsanitize=signed-integer-overflow,implicit-integer-sign-change,implicit-signed-integer-truncation

Continuation of !79 (merged)

added 3 commits

• 420344da - Fix integer overflow in cabac psy-trellis
• a19dd6d6 - Fix integer overflow in cavlc trellis
• 3ac55af4 - Fix implicit integer sign change and truncation

Compare with previous version

changed the description

mentioned in merge request !79 (merged)

requested review from @gramner

approved this merge request

added 8 commits

• 3ac55af4...6c142bba - 5 commits from branch videolan:master
• 3a08e36e - Fix integer overflow in cabac psy-trellis
• 78520340 - Fix integer overflow in cavlc trellis
• 5bb1f1b1 - Fix implicit integer sign change and truncation

Compare with previous version

enabled an automatic merge when the pipeline for 5bb1f1b1 succeeds

merged

mentioned in merge request !95 (merged)