Remove TCK tests from JDK9 Flow integration

Since the JDK9 Flow integration is now implemented as thin
wrappers around the Reactive Streams integration, there is no need
for such thorough testing, and additional tests would only cause
the overhead of needing to fix two copies at once when changing
the Reactive Streams integration.

reactive/kotlinx-coroutines-jdk9/build.gradle

@@ -3,36 +3,9 @@
  */
 targetCompatibility = 9
 
-
 dependencies {
     compile project(":kotlinx-coroutines-reactive")
     compile "org.reactivestreams:reactive-streams-flow-adapters:$reactive_streams_version"
-    testCompile "org.reactivestreams:reactive-streams-tck:$reactive_streams_version"
-}
-
-task testNG(type: Test) {
-    useTestNG()
-    reports.html.destination = file("$buildDir/reports/testng")
-    include '**/*ReactiveStreamTckTest.*'
-    // Skip testNG when tests are filtered with --tests, otherwise it simply fails
-    onlyIf {
-        filter.includePatterns.isEmpty()
-    }
-    doFirst {
-        // Classic gradle, nothing works without doFirst
-        println "TestNG tests: ($includes)"
-    }
-}
-
-task checkJdk11() {
-    // only fail w/o JDK_11 when actually trying to compile, not during project setup phase
-    doLast {
-        if (!System.env.JDK_11) {
-            throw new GradleException("JDK_11 environment variable is not defined. " +
-                    "Can't build against JDK 11 runtime and run JDK 11 compatibility tests. " +
-                    "Please ensure JDK 11 is installed and that JDK_11 points to it.")
-        }
-    }
 }
 
 compileTestKotlin {
@@ -41,13 +14,6 @@ compileTestKotlin {
 
 compileKotlin {
     kotlinOptions.jvmTarget = "9"
-    kotlinOptions.jdkHome = System.env.JDK_11
-    dependsOn(checkJdk11)
-}
-
-test {
-    dependsOn(testNG)
-    reports.html.destination = file("$buildDir/reports/junit")
 }
 
 tasks.withType(dokka.getClass()) {