Remove Java 8 test restriction (#1019)

instrumentation/jaxrs/jaxrs-2.0/jaxrs-2.0.gradle

@@ -49,12 +49,3 @@ dependencies {
 }
 
 test.dependsOn resteasy31Test
-
-// Until custom source sets can use minJavaVersionForTests separately from other tests
-// force this one test to run on java8 only
-resteasy31Test {
-  onlyIf {
-    String java8Home = findJavaHome(JavaVersion.VERSION_1_8)
-    java8Home != null && executable == toExecutable(java8Home)
-  }
-}