Always fork jvm for compile, even when using the Gradle runtime jvm

Fixes spurious build failures from OOM

build.gradle.kts

@@ -31,6 +31,7 @@ subprojects {
     tasks.withType<JavaCompile> {
         options.encoding = Charsets.UTF_8.name()
         options.release = 21
+        options.isFork = true
     }
     tasks.withType<Javadoc> {
         options.encoding = Charsets.UTF_8.name()