Previous incarnation of MockMvc Kotlin DSL tried to reuse directly
Java APIs like ModelResultMatchers or StatusResultMatchers, but
when using multiple matchers in DSL blocks like model { } or
status { }, only the last statement was taken in account which
was very confusing.
This refactoring provides dedicated Kotlin DSLs for matchers.
The main API breaking changes is that functions like isOk() need to be
invoked with the parenthesis, isOk is not supported anymore (on purpose).
Closes gh-24103
d04c5f8b2c