Fix `OAuth2ResourceServerConfigurer` member variable using Java 9+ feature

[marcusdacoregio]

The code in the 5.7.x branch is requiring JDK 11

spring-security/config/src/main/java/org/springframework/security/config/annotation/web/configurers/oauth2/server/resource/OAuth2ResourceServerConfigurer.java

Line 162 in f04cd64

new LinkedHashMap<>(Map.of(CsrfException.class, new AccessDeniedHandlerImpl())),

We should fix this and the build should fail if using a language feature that is not compatible with JDK 8.

[marcusdacoregio]

Fixed via 60ed360