The assembly code generated by MSVC for at least some signed comparisons involving atomic variables incorrectly uses unsigned conditional jumps instead of signed ones. In particular, the checks in isc_log_wouldlog() are affected in a way which breaks logging on Windows and thus also all system tests involving a named instance. Work around the issue by assigning the values returned by atomic_load_acquire() calls in isc_log_wouldlog() to local variables before performing comparisons.
(cherry picked from commit 4c4f5ccc)
Closes #1742 (closed)