Episerver - update 355

Steps to reproduce:
Define a content type via Definitions Api.
Note: A "regularExpression" validation is added to a string property but its pattern is invalid. For example, "pattern": "[0-9]++"

{
	"name": "PageRegExValidationInvalidCase3",
	"baseType": "Page",
	"editSettings": {
		"available": true,
		"order": 0
	},
	"properties": [
        {
			"name": "String1",
			"dataType": "PropertyString",
			"validation": [
				{
					"name": "RegularExpression",
					"severity": "error",
                    "pattern": "[0-9]++",
					"errorMessage": "String 1: pattern is invalid"

				}
			]
		},
        {
			"name": "StringList1",
			"dataType": "PropertyStringList",
			"validation": [
				{
					"name": "itemRegularExpression",
					"severity": "error",
                    "pattern": "[0-9]++",
					"errorMessage": "String List 1: pattern is invalid"

				}
			]
		}
	]
}

Expected result: 
Content management is created with invalid pattern return 400- Bad Request.

Actual result:
Content type is created with invalid pattern. 

Content management is created with invalid pattern return 500.

Steps to reproduce:

1. Enable multiple languages like this:
   
2. Set root to enable all the languages and set the fallback language to "en" for every language except en.
3. On page Alloy Plan, set simple address to "alloy".
4. Create different language versions of Alloy plan and set simple address to "alloy" for all the different language versions.
5. Go to the different language versions by using their simple address. So for German go to site.com/de/alloy or Swedish site.com/sv/alloy.

Expected result:

The different language versions of the page should be displayed.

Actual result:

Sometimes, the English version is displayed even if there is a language version available.

There are some accessibility issues with the login page (Util/login.aspx) according to WCAG 2.1.

<li>
    <label for="UserName">Name</label>
    <input name="LoginControl$UserName" type="text" id="LoginControl_UserName" />
    <span id="LoginControl_RequiredFieldValidator1" style="display:none;">­     </span>
</li>