[Gradle, JS] Add browser to test js composite build

#KT-37954 fixed

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/js-composite-build/app/build.gradle.kts

@@ -11,6 +11,11 @@ repositories {
 kotlin.js {
     binaries.executable()
     nodejs()
+    browser()
+}
+
+tasks.named("browserTest") {
+    enabled = false
 }
 
 rootProject.tasks

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/js-composite-build/lib/build.gradle.kts

@@ -10,7 +10,14 @@ repositories {
     mavenLocal()
 }
 
-kotlin.target.nodejs()
+kotlin.js {
+    nodejs()
+    browser()
+}
+
+tasks.named("browserTest") {
+    enabled = false
+}
 
 rootProject.tasks
     .withType(org.jetbrains.kotlin.gradle.targets.js.npm.tasks.KotlinNpmInstallTask::class.java)

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/ir/KotlinJsIrTarget.kt

@@ -59,7 +59,12 @@ constructor(
             it.description = "Run js on all configured platforms"
         }
 
-    private var testsConfigured: Boolean = false
+    private val configureTestSideEffect: Unit by lazy {
+        compilations.matching { it.name == KotlinCompilation.TEST_COMPILATION_NAME }
+            .all { compilation ->
+                compilation.binaries.executableIrInternal(compilation)
+            }
+    }
 
     private val browserLazyDelegate = lazy {
         project.objects.newInstance(KotlinBrowserJsIr::class.java, this).also {
@@ -105,13 +110,7 @@ constructor(
     }
 
     private fun KotlinJsIrSubTarget.configureSubTarget() {
-        compilations.matching { it.name == KotlinCompilation.TEST_COMPILATION_NAME }
-            .all { compilation ->
-                if (!testsConfigured) {
-                    testsConfigured = true
-                    compilation.binaries.executableIrInternal(compilation)
-                }
-            }
+        configureTestSideEffect
         configure()
     }