Prevent error with JDK19 related to Thread.Builder

[jbescos]

Prevents JDK19 compilation error once this branch is update with JDK19 changes:
#5124 (comment)

Running mvn clean install -DskipTests in jersey/containers/grizzly2-http:

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  7.080 s
[INFO] Finished at: 2022-08-18T09:24:10+02:00
[INFO] ------------------------------------------------------------------------
jbescos@jbescos-TECRA-X40-E:~/workspace/jersey/containers/grizzly2-http$ mvn --version
Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
Maven home: /home/jbescos/programs/apache-maven-3.6.3
Java version: 19-ea, vendor: Oracle Corporation, runtime: /home/jbescos/programs/java/jdk-19
Default locale: en, platform encoding: UTF-8
OS name: "linux", version: "5.4.0-107-generic", arch: "amd64", family: "unix"