testing: Increase memory for guest hosts to run Debian trixie

testing: Increase memory for guest hosts to run Debian trixie

While some increase was necessary anyway because the idle system requires
about 5-10 MiB more memory, the main issue is resolving the code line and
function name in case of a memory leak.  Calling addr2line requires a lot
more memory than before.  Using backtraces via libbfd doesn't help either
because the trigger is the bfd_find_nearest_line() call we use as well.
And because we'd try to resolve all symbols that way (for whitelisting),
the memory overhead would be even higher and affect every shutdown, even
if no leak occurred.  It also causes a significant time overhead (running
all tests took 75m instead of 48m).

I also tested switching to ASAN/LSAN.  The peak memory usage is slightly
higher than when using libbfd, but enabling it also increased the runtime
overhead a lot (the daemon and swanctl both required about 10-20 MiB more
memory, not just during the shutdown).