New option --dxv-path is added for dxc mode to set the installation path for dxv.
If cannot find dxv, a warning will be report.
dxv will be executed with command line dxv file_name -o file_name.
It will validate and sign the file and overwrite it.
Differential Revision: https://reviews.llvm.org/D141705
The DXC driver tests don't really belong mixed in with the toolchain
tests. This pulls them out to their own file and moves the
SimpleDiagnosticConsumer into a header so it can be used by both DXC and
toolchain tests.
fast-forwarded.