Use `resetBenignCodeGenOptions()` from clang dependency scanner to clear
the swift explicit module build cc1 arguments. This fixes the problem
that CurrentWorkingDirectory is leaking through
`-fcoverage-compilation-dir` that can cause extra module variants when
caching is enabled. This also avoid the duplicating the logics for
clearing CodeGen options inside Swift.
rdar://151395300
(cherry picked from commit 531227d4b9)
