I sheilded a MSVC pragma, silenced some classes of warnings.

One of the classes involves an overload that hides a member function. I filed a
bug to make certain that this isn't masking a coding error:

https://b.corp.google.com/issues/22117892

Change-Id: I7090cddc78880c9ee7814aecc72cc107003dfede
Reviewed-on: https://swiftshader-review.googlesource.com/3483Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Greg Hartman <ghartman@google.com>