Migrate discovery-ec2 QA tests to javaRestTest (#119384) (#120511)

No need for all this Gradle magic any more, we can just test the
discovery behaviour directly using Java REST tests.

Author: DaveCTurner

plugins/discovery-ec2/build.gradle

@@ -31,6 +31,8 @@ dependencies {
   api "joda-time:joda-time:2.10.10"
 
   javaRestTestImplementation project(':plugins:discovery-ec2')
+  javaRestTestImplementation project(':test:fixtures:aws-fixture-utils')
+  javaRestTestImplementation project(':test:fixtures:aws-ec2-fixture')
   javaRestTestImplementation project(':test:fixtures:ec2-imds-fixture')
 
   internalClusterTestImplementation project(':test:fixtures:ec2-imds-fixture')
@@ -101,11 +103,6 @@ tasks.withType(Test).configureEach {
   }
 }
 
-tasks.named("check").configure {
-  // also execute the QA tests when testing the plugin
-  dependsOn 'qa:amazon-ec2:check'
-}
-
 tasks.named("thirdPartyAudit").configure {
   ignoreMissingClasses(
           // classes are missing