implement "possible InvalidOperationException" analyzer like ReSharper

[matthargett]

In react-native-windows, we recently had a bug that should have been caught by static analysis. Even when updating to the latest prerelease nuget packages, no Roslyn analyzer detected the bug. ReSharper, however, did:

[sharwell]

@matthargett Do you have a link to the original bug to provide a bit more context around what is being analyzed/detected?

[matthargett]

Here's the diff where the bug was fixed:
microsoft/react-native-windows@1ed199c

The non-UWP version of ContentLength could return null(!?), so the cast to ulong would fail. ReSharper warned on the issue in the IDE, but we want to get this feedback in a Roslyn analyzer we can run in our CI for free. Casting potential null to non-nullable value type is one way to generically classify this, but ReSharper identified it as potential InvalidOperationException. Whatever the phrasing, that's the core bug class we'd like to detect and fail the build on. /cc @rozele @kevinvangelder