tool.drcacheoff.burst_* tests failing flakily on Windows CI

We've seen these tests fail on Appveyor in #4058. I'm filing a dedicated issue to separate that out. These have also been seen to fail on GA Server2016 (#4131 (closed)) and are now on the ignore list. All are 32-bit-only:

                'code_api|tool.drcacheoff.burst_replace' => 1, # i#4131
                'code_api|tool.drcacheoff.burst_traceopts' => 1, # i#4131
                'code_api|tool.drcacheoff.burst_replaceall' => 1, # i#4131
                'code_api|tool.drcacheoff.burst_static' => 1, # i#4486

As shown there, burst_static may have a different failure reason than the others: #4486. Needs investigation.