Remove unused fScriptChecks parameter from CheckInputs (Matt Corallo)
Pull request description:
fScriptChecks = false just short-circuits the entire function, so passing it in is entirely useless. This is extracted from #13233 /cc TheBlueMatt. Recommend reviewing with `git show --ignore-all-space`, i.e.: https://github.com/bitcoin/bitcoin/pull/13868/files?w=1
Backport of Core PR13868