* Clean up unnecessary workarounds on the build project.
* Remove the need to specify the content root relative to the solution
and use a solution based on an assembly level attribute on the test
assembly created at build time.
* Remove non parameterless constructors.
* Add support for creating specialized factories from the base factory
and keep track of "child" factories for disposal.
* Add support for creating clients that handle cookies and redirects
automatically.
- #6648
- a different take on #4871
- `DateTime` can also round-trip `DateTimeKind.UTC` with `[DataType("datetimeoffset")]` or `[UIHint("datetimeoffset")]`
- since they're now handled differently by default, add more `DateTime` tests
- expand tests involving `Html5DateRenderingMode.CurrentCulture`
nits: make VS-suggested changes to files updated in this PR
- #5209
- update affected `HtmlHelperValiationSummaryTest` and functional tests
- add `ValidationSummaryTagHelperTest` tests to cover related scenarios
##### Behaviour changes when no errors exist for the model:
###### Tag helper
``` html
<div asp-validation-summary="ModelOnly" class="order"><h3>Oopsie<h3></div>
```
previously generated
``` html
<div class="order validation-summary-errors"><h3>Oopsie</h3><ul><li style="display:none"></li>
</ul></div>
```
and now generates
``` html
<div class="order"><h3>Oopsie</h3></div>
```
###### HTML helper
``` c#
@Html.ValidationSummary(excludePropertyErrors: true, message: "Oopsie")
```
previously generated
``` html
<div class=\"validation-summary-errors\"><span>Oopsie</span>
<ul><li style=\"display:none\"></li>
</ul></div>
```
and now generates nothing (`@HtmlString.Empty`).
Javier Calvarro Nelson
Doug Bunting
Jass Bagga
Ryan Brandenburg
N. Taylor Mullen