Disable InvokeOnEventsThreadRunsAsynchronously test on netfx (dotnet#…

…38662)

And avoid the whole suite from hanging by changing an ~3hr timeout to a 30s timeout.

.NET Core 3.0.0-preview6

.NET Core 2.2.5

.NET Core 2.2.5 dependencies

.NET Core 2.1.11

.NET Core 2.1.11 dependencies

.NET Core 1.1.13

.NET Core 1.0.16

.NET Core 3.0.0 preview5.19224.8

.NET Core 3.0.0 preview4