Fix race condition in multi_threaded_observable_map test - #1550

Fix race condition in multi_threaded_observable_map test#1550

Ryan Shepherd (DefaultRyan) merged 2 commits into

mastermicrosoft/cppwinrt:masterfrom

1549-bug-test-multi_threaded_observable_map-fails-randomlymicrosoft/cppwinrt:1549-bug-test-multi_threaded_observable_map-fails-randomlyCopy head branch name to clipboard