Standarize Mock Request Paths

[jzheaux]

Historically, Spring Security tests have set the servlet path to indicate the path of a MockHttpServletRequest. This was needed for AntPath and MvcRequestMatcher to correctly match the specified request path.

This can leave MockHttpServletRequest in an inconsistent state since requestURI is null while servletPath has a value.

For example, PathPatternRequestMatcher does not use the servlet path. For tests to continue working both before and after the migration from AntPath/MvcRequestMatcher to PathPatternRequestMatcher, the mock requests should have a consistent representation of path in getRequestURI and getServletPath.

This ticket should ensure that the requestURI and servletPath have consistent values in Spring Security tests.