Fix publication validator not looking in the local maven repository (#1880)

During the change of the publication validator, a bug was
introduced that led to MavenPublicationValidator being run not on
the artifacts from the local Maven repository but on classfiles
from the corresponding subproject. This is a problem because this
test is for the behavior of the atomicfu plugin, which could in
theory produce nice classfiles in one place but wrong ones in the
other, and the only important thing to test is whether the
published classfiles are good.

Now, this is fixed.

Author: dkhalanskyjb

publication-validator/build.gradle

@@ -4,6 +4,8 @@
 
 apply from: rootProject.file("gradle/compile-jvm.gradle")
 
+def coroutines_version = version // all modules share the same version
+
 repositories {
     mavenLocal()
     mavenCentral()
@@ -14,8 +16,6 @@ dependencies {
     testCompile 'junit:junit:4.12'
     testCompile 'org.apache.commons:commons-compress:1.18'
     testCompile 'com.google.code.gson:gson:2.8.5'
-    testCompile project(':kotlinx-coroutines-core')
-    testCompile project(':kotlinx-coroutines-android')
 }
 
 compileTestKotlin {
@@ -26,7 +26,14 @@ def dryRunNpm = properties['dryRun']
 
 test {
     onlyIf { dryRunNpm == "true" } // so that we don't accidentally publish anything, especially before the test
-    doFirst { println "Verifying publishing version $version" } // all modules share the same version
+    doFirst {
+        println "Verifying publishing version $coroutines_version"
+        // we can't depend on the subprojects because we need to test the classfiles that are published in the end.
+        // also, we can't put this in the `dependencies` block because the resolution would happen before publication.
+        classpath += project.configurations.detachedConfiguration(
+                project.dependencies.create("org.jetbrains.kotlinx:kotlinx-coroutines-core:$coroutines_version"),
+                project.dependencies.create("org.jetbrains.kotlinx:kotlinx-coroutines-android:$coroutines_version"))
+    }
     environment "projectRoot", project.rootDir
     environment "deployVersion", version
     if (dryRunNpm == "true") { // `onlyIf` only affects execution of the task, not the dependency subtree