Disabling the gradle wrapper doesn't work in some cases

[fbricon]

If the gradle wrapper is disabled and no gradle home variable is defined, the GradleProjectImporter.getGradleDistribution returns the wrapper anyways, instead of the default gradle distro (DEFAULT_DISTRIBUTION == GradleDistribution.fromBuild() == wrapper):
https://github.com/eclipse/eclipse.jdt.ls/blob/43a78f7c339f41d7cb3c4d6d23e3fe18b74c29ef/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/managers/GradleProjectImporter.java#L120-L124.

And if the GradleProjectImporterTest.testDisableGradleWrapper runs in an environment which defines a gradle home, then the test fails L109:

https://github.com/eclipse/eclipse.jdt.ls/blob/43a78f7c339f41d7cb3c4d6d23e3fe18b74c29ef/org.eclipse.jdt.ls.tests/src/org/eclipse/jdt/ls/core/internal/managers/GradleProjectImporterTest.java#L107-L109

[fbricon]

should be

DEFAULT_DISTRIBUTION = GradleDistribution.forVersion(GradleVersion.current().getVersion());