Make use of JavaExecSpec.getJvmArguments()

[wilkinsona]

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:

spring-boot/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/plugin/JavaPluginAction.java

Lines 177 to 182 in 57a4eb8

	run.getConventionMapping().map("jvmArgs", () -> {
	if (project.hasProperty("applicationDefaultJvmArgs")) {
	return project.property("applicationDefaultJvmArgs");
	}
	return Collections.emptyList();
	});

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.