Build and verify runnable samples with gradle.

libraries/stdlib/samples/build.gradle

@@ -0,0 +1,20 @@
+apply plugin: 'kotlin'
+
+dependencies {
+    compile project(':kotlin-stdlib-jre8')
+    testCompile project(':kotlin-test:kotlin-test-junit')
+}
+
+sourceSets {
+    test.kotlin.srcDir 'test'
+}
+
+compileTestKotlin {
+    kotlinOptions.jdkHome = JDK_18
+}
+
+kotlin.experimental.coroutines 'enable'
+
+test {
+    executable = "$JDK_18/bin/java"
+}