testsuite result updates for x86_64-w64-mingw32

[Eric Botcazou]

> It's built with --disable-sjlj-exceptions --with-dwarf2
> 
> https://github.com/Alexpux/MINGW-packages/blob/master/mingw-w64-gcc/PKGBUILD
> #L150

Then, if both the base compiler and the compiler to be built are configured 
that way, there is no reason why this cannot work.

What's a little strange is that there is a .cold part in the backtrace:

#14 0x015fd511 in uw_init_context_1.cold ()
at ../../../gcc-8-20181214/libgcc/unwind-dw2.c:1386

and this shouldn't happen for the compiler built during stage #1.  Do you add 
-O2 to the STAGE1_CFLAGS or some such?  If so, can you lower it to -O1 or -O0?

-- 
Eric Botcazou