Add URI based MockHttpServletRequestBuilder constructors

This commit adds new MockHttpServletRequestBuilder constructors
with an URI parameter in addition to the URL template + URL variables
existing ones.

It gives more control on how the URL is built, allowing for example to
use URL variables containing '/' character with proper encoding.

Issue: SPR-11441
Improve method order in MockMvcRequestBuilders
Give meaningful names to SprXxxTests in spring-test