Get platform for scripts from script definition

Introduce 'platform' property in KotlinScripDefinition (should have a value which exists in TargetPlatform.ALL_KINDS)

^KT-27684 Fixed

idea/testData/gradle/highlighting/ktsInJsProject/build.gradle.kts

@@ -0,0 +1,21 @@
+import org.jetbrains.kotlin.gradle.tasks.Kotlin2JsCompile
+
+plugins {
+    id("kotlin2js") version "1.3.10"
+}
+
+dependencies {
+    implementation(kotlin("stdlib-js", "1.3.10"))
+}
+
+repositories {
+    jcenter()
+}
+
+tasks {
+    "compileKotlin2Js"(Kotlin2JsCompile::class) {
+        kotlinOptions {
+            metaInfo = true
+        }
+    }
+}

idea/testData/gradle/highlighting/ktsInJsProject/settings.gradle

@@ -0,0 +1,11 @@
+pluginManagement {
+    resolutionStrategy {
+        eachPlugin {
+            if (requested.id.id == "kotlin2js") {
+                useModule("org.jetbrains.kotlin:kotlin-gradle-plugin:${requested.version}")
+            }
+        }
+    }
+}
+
+rootProject.name = 'test'