Spring Boot has honored @Primary for selecting which candidate bean
@MockBean and @SpyBean should mock or spy since Spring Boot 1.4.3;
however, the support for @Primary was not ported from Spring Boot to
Spring Framework's new Bean Overrides feature in the TestContext
framework.
To address that, this commit introduces support for @Primary for
selecting bean overrides -- for example, for annotations such as
@TestBean, @MockitoBean, and @MockitoSpyBean.
See https://github.com/spring-projects/spring-boot/issues/7621
Closes gh-33819