CommandLineUtils is incompatible with JDK 21

[cushon]

annotation-file-utilities/src/main/java/org/checkerframework/afu/scenelib/util/CommandLineUtils.java imports com.sun.tools.javac.main.CommandLine:

annotation-tools/annotation-file-utilities/src/main/java/org/checkerframework/afu/scenelib/util/CommandLineUtils.java

Line 3 in f61bfc9

import com.sun.tools.javac.main.CommandLine;

That internal javac API is being renamed in JDK 21, to jdk.internal.opt/jdk.internal.opt.CommandLine

The upstream change is

• openjdk/jdk@a80552e
• https://bugs.openjdk.org/browse/JDK-8236919