[7.x] Optimize which Rest resources are used by the Rest tests… (#53766)

This should help with Gradle's incremental compile such that projects
only depend upon the resources they use.

related #52114

plugins/discovery-ec2/build.gradle

@@ -40,6 +40,12 @@ dependencies {
   compile "com.fasterxml.jackson.core:jackson-annotations:${versions.jackson}"
 }
 
+restResources {
+  restApi {
+    includeCore '_common', 'cluster', 'nodes'
+  }
+}
+
 dependencyLicenses {
   mapping from: /aws-java-sdk-.*/, to: 'aws-java-sdk'
   mapping from: /jackson-.*/, to: 'jackson'

plugins/discovery-ec2/qa/amazon-ec2/build.gradle

@@ -32,6 +32,12 @@ dependencies {
   testCompile project(path: ':plugins:discovery-ec2', configuration: 'runtime')
 }
 
+restResources {
+  restApi {
+    includeCore '_common', 'cluster', 'nodes'
+  }
+}
+
 final int ec2NumberOfNodes = 3
 
 Map<String, Object> expansions = [