Verify fast typing and bind parsing scenarios

[SteveSandersonMS]

To verify #11438, deploy a server-side Blazor app to an Azure location on the other side of the world, so you have maximum round-trip time.

1. Have a textbox with bind-value:event="oninput", also wired up to display the typed value somewhere else in the UI, so it updates on every keystroke. Verify you can type much faster than the ping time to the server (e.g., 10 chars/sec, if the server is 300ms away) and none of the keystrokes are dropped or incorrectly ordered in the output. Verify you can position the cursor somewhere in the middle of an existing string, type fast, and the cursor position doesn't incorrectly jump to the end like it did before.

2. Have a textbox bound to an int. Verify that when entering a non-parseable value (empty string, some non-numeric value, etc.) that when you tab out it reverts to the previous valid value.

3. Same as 2, but with bind-value:event="oninput", so now you aren't allowed to enter any keystrokes that would make it unparseable. Or rather you can type them, but it will revert back to the previous value. This is kind of surprising in some ways (e.g., you can't clear the textbox completely, as it will revert to 0) but is the behavior by design now.

[SteveSandersonMS]

Verified exactly as described above.

[SteveSandersonMS]

Also, verified the fast-typing scenario both with WebSockets disabled (the Azure App Service default) and enabled. It works correctly in both cases, and like you'd expect, is far less laggy with WebSockets enabled.