This change now also makes it so that when rr::Print is enabled, it will
output to stdout and to the debugger, if available. For now, that means
it calls OutputDebugString on Windows. This is useful when it is
difficult to capture stdout (e.g. debugging Chrome).

Also, you can now modify Reactor.cpp and uncomment
`#define RR_PRINT_OUTPUT_TYPE_STUB` to stub out the function itself.
This is useful in combination with ENABLE_RR_EMIT_PRINT_LOCATION in that
debugging the code-gen assembly allows you to inspect the string
argument to rr::DebugPrintf and see exactly where you are in Reactor
code without paying the performance cost of actually printing.

Bug: b/158678105
Change-Id: Ie1bd85888405e189200c0e5f8f3449551327e0ab
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/45669
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>