GH-386: Restore interrupted thread status in provided backoff policies

[mlichtblau]

See GH-386

[artembilan]

See error for code format:

 Error:  Failed to execute goal io.spring.javaformat:spring-javaformat-maven-plugin:0.0.39:validate (default) on project spring-retry: Formatting violations found in the following files:
Error:   * /home/runner/work/spring-retry/spring-retry/src/test/java/org/springframework/retry/backoff/UniformRandomBackOffPolicyTests.java
Error:  
Error:  Run `spring-javaformat:apply` to fix.

Please, add your name to the @author for all the effected classes.
Also, please, update their copyright to the current year.

Thank you!

[artembilan]

... and back-ported as 4f104e1 after fixing conflicts.

Thank you, @mlichtblau , for contribution; looking forward for more!