Prep D8 default instead of CompatDX in build/soong

Bug: 69329508
Test: m checkbuild tests
Change-Id: Ibaa2d787c644cf25104af78305a6eed16028dcf0

java/builder.go

@@ -441,7 +441,7 @@ func TransformClassesJarToDexJar(ctx android.ModuleContext, outputFile android.W
 
 	rule := dx
 	desc := "dx"
-	if ctx.AConfig().IsEnvTrue("USE_D8_DESUGAR") {
+	if ctx.Config().UseD8Desugar() {
 		rule = d8
 		desc = "d8"
 	}