Adjust to JavaCore.defaultRootModules deprecation

[akurtakov]

Use the new method that filters based on the release. If release option is not set, use target and if it's not there too use the latest version.

[akurtakov]

@stephan-herrmann As this is continuation of eclipse-jdt/eclipse.jdt.core#2786 (in a way), would you please review?

[stephan-herrmann]

@stephan-herrmann As this is continuation of eclipse-jdt/eclipse.jdt.core#2786 (in a way), would you please review?

Sorry for the delay.

Strictly speaking, https://bugs.openjdk.org/browse/JDK-8205169 specifies that the old behavior should be retained only when using --release:

At compile-time, the JDK 9/10 policy for root modules will still be used when targeting 9 and 10 with --release.

So, in jdt.core I use this idiom:

	String release = JavaCore.ENABLED.equals(getOption(JavaCore.COMPILER_RELEASE, true))
					? getOption(JavaCore.COMPILER_COMPLIANCE, true) : null;

But the change has another problem: option COMPILER_RELEASE has values ENABLED|DISABLED, which are not proper values for JavaCore.defaultRootModules()

[akurtakov]

Ah, I missed that . New PR is in the prep.

[stephan-herrmann]

Ah, I missed that . New PR is in the prep.

thanks