The `Display` implementation for `Backtrace` used to print
stack backtrace:
but that print was later removed. To make the existing test pass, the
print was added to the existing test. But it doesn't make sense to check
for something that the test itself does since that will not detect any
regressions in the implementation of `Backtrace`. Fully remove the
checks.
The original PR which disabled these only mentions them being broken on
i686 msvc. Let's try to see if we can reenable this test for msvc (both
32-bit and 64-bit).
