Conditionally disable :example-frontend-js for snapshot train

It doesn't work properly with new JS IR BE because it depends on a really old plugin version

build.gradle

@@ -134,6 +134,10 @@ allprojects {
 apply plugin: "binary-compatibility-validator"
 apiValidation {
     ignoredProjects += unpublished + ["kotlinx-coroutines-bom"]
+    if (build_snapshot_train) {
+        ignoredProjects.remove("site")
+        ignoredProjects.remove("example-frontend-js")
+    }
     ignoredPackages += "kotlinx.coroutines.internal"
 }
 
@@ -305,4 +309,4 @@ knit {
     moduleRoots = [".", "integration", "reactive", "ui"]
 }
 
-knitPrepare.dependsOn getTasksByName("dokka", true)
+knitPrepare.dependsOn getTasksByName("dokka", true)

settings.gradle

@@ -11,11 +11,11 @@ def module(String path) {
     include(name)
     project(":$name").projectDir = file(path)
 }
-
+def prop = System.getProperty("build_snapshot_train")
+ext.build_snapshot_train = prop != null && prop != ""
 // ---------------------------
 
 include('benchmarks')
-include('site')
 
 include "kotlinx-coroutines-core"
 
@@ -39,6 +39,9 @@ module('ui/kotlinx-coroutines-javafx')
 module('ui/kotlinx-coroutines-swing')
 
 module('js/js-stub')
-module('js/example-frontend-js')
+if (!build_snapshot_train) {
+    module('js/example-frontend-js')
+    include('site')
+}
 
 module('publication-validator')