SpringBoot Make use of JavaExecSpec.getJvmArguments()

Gradle 8.1 will add and jvmArguments property to JavaExecSpec. We should be able to use this new property instead of our current convention mapping:

https://github.com/spring-projects/spring-boot/blob/57a4eb88dbef7c1cf25eaa27baaf21cdd0e45083/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/plugin/JavaPluginAction.java#L177-L182

Unless we wait until we've raised our Gradle baseline to 8.1, we'll have to check the version of Gradle that we're running against or perhaps use reflection to maintain compatibility with older versions of Gradle.