Fix flaky JS tests.

They are disabling error for using JS/Legacy backend via System property
by passing it to the Kotlin Daemon. But daemon may already be started
and not contain such property.

Workaround for now is to use 'in-process' compilation for such cases.

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/NewMultiplatformIT.kt

@@ -322,6 +322,13 @@ class NewMultiplatformIT : BaseGradleIT() {
             ).map { ":compileKotlin$it" }
 
         with(libProject) {
+            gradleProperties().appendText(
+                """
+                
+                systemProp.kotlin.js.compiler.legacy.force_enabled=true
+                kotlin.compiler.execution.strategy=in-process
+                """.trimIndent()
+            )
             build(
                 "publish",
                 options = defaultBuildOptions().copy(jsCompilerType = jsCompilerType)
@@ -378,6 +385,14 @@ class NewMultiplatformIT : BaseGradleIT() {
         with(appProject) {
             setupWorkingDir()
 
+            gradleProperties().appendText(
+                """
+                
+                systemProp.kotlin.js.compiler.legacy.force_enabled=true
+                kotlin.compiler.execution.strategy=in-process
+                """.trimIndent()
+            )
+
             // we use `maven { setUrl(...) }` because this syntax actually works both for Groovy and Kotlin DSLs in Gradle
             gradleBuildScript().appendText("\nrepositories { maven { setUrl(\"$libLocalRepoUri\") } }")
 
@@ -973,6 +988,14 @@ class NewMultiplatformIT : BaseGradleIT() {
         val appProject = Project("sample-app", gradleVersion, "new-mpp-lib-and-app")
 
         val buildOptions = hmppFlags.buildOptions
+        libProject.setupWorkingDir()
+        libProject.gradleProperties().appendText(
+            """
+                
+                systemProp.kotlin.js.compiler.legacy.force_enabled=true
+                kotlin.compiler.execution.strategy=in-process
+                """.trimIndent()
+        )
         @Suppress("DEPRECATION")
         libProject.build(
             "publish",
@@ -986,6 +1009,14 @@ class NewMultiplatformIT : BaseGradleIT() {
         with(appProject) {
             setupWorkingDir()
 
+            gradleProperties().appendText(
+                """
+                
+                systemProp.kotlin.js.compiler.legacy.force_enabled=true
+                kotlin.compiler.execution.strategy=in-process
+                """.trimIndent()
+            )
+
             val pathPrefix = "metadataDependency: "
 
             gradleBuildScript().appendText(
@@ -1463,6 +1494,15 @@ class NewMultiplatformIT : BaseGradleIT() {
 
     @Test
     fun testJsDceInMpp() = with(Project("new-mpp-js-dce", gradleVersion)) {
+        setupWorkingDir()
+        gradleProperties().appendText(
+            """
+                
+                systemProp.kotlin.js.compiler.legacy.force_enabled=true
+                kotlin.compiler.execution.strategy=in-process
+                """.trimIndent()
+        )
+
         @Suppress("DEPRECATION")
         build(
             "runRhino",
@@ -1593,6 +1633,8 @@ class NewMultiplatformIT : BaseGradleIT() {
 
     @Test
     fun testIncrementalCompilation() = with(Project("new-mpp-jvm-js-ic", gradleVersion)) {
+        setupWorkingDir()
+
         build("build") {
             assertSuccessful()
         }
@@ -1634,6 +1676,14 @@ class NewMultiplatformIT : BaseGradleIT() {
         setupWorkingDir()
         gradleBuildScript().modify(::transformBuildScriptWithPluginsDsl)
 
+        gradleProperties().appendText(
+            """
+                
+                systemProp.kotlin.js.compiler.legacy.force_enabled=true
+                kotlin.compiler.execution.strategy=in-process
+                """.trimIndent()
+        )
+
         val groupDir = "build/repo/com/example/"
 
         build(":mpp-lib:publish") {

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/new-mpp-jvm-js-ic/app/gradle.properties

@@ -1 +0,0 @@
-kotlin.daemon.jvmargs=-Dkotlin.js.compiler.legacy.force_enabled=true

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/new-mpp-jvm-js-ic/configure-targets.gradle

@@ -1,10 +1,9 @@
 apply plugin: "kotlin-multiplatform"
 
 kotlin {
-    targets {
+    jvm {}
-        fromPreset(presets.jvm, 'jvm')
+    js(IR) {}
-        fromPreset(presets.js, 'js')
+
-    }
     sourceSets {
         commonMain {
             dependencies {

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/new-mpp-jvm-js-ic/gradle.properties

@@ -1,2 +0,0 @@
-kotlin.js.compiler=legacy
-kotlin.daemon.jvmargs=-Dkotlin.js.compiler.legacy.force_enabled=true

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/new-mpp-jvm-js-ic/lib/gradle.properties

@@ -1 +0,0 @@
-kotlin.daemon.jvmargs=-Dkotlin.js.compiler.legacy.force_enabled=true