Kotlin Facet: Fix reading of v1 configuration

Favor language/api version specified in <versionInfo> element
in case it differs from the one in
<option name="_commonCompilerArguments">

#KT-16861 Fixed

Original commit: 2bb7bdfc3f

jps/jps-common/src/org/jetbrains/kotlin/config/facetSerialization.kt

@@ -33,7 +33,10 @@ private fun readV1Config(element: Element): KotlinFacetSettings {
     return KotlinFacetSettings().apply {
         val useProjectSettings = element.getOptionValue("useProjectSettings")?.toBoolean()
 
-        val targetPlatformName = element.getOptionBody("versionInfo")?.getOptionValue("targetPlatformName")
+        val versionInfoElement = element.getOptionBody("versionInfo")
+        val targetPlatformName = versionInfoElement?.getOptionValue("targetPlatformName")
+        val languageLevel = versionInfoElement?.getOptionValue("languageLevel")
+        val apiLevel = versionInfoElement?.getOptionValue("apiLevel")
         val targetPlatform = TargetPlatformKind.ALL_PLATFORMS.firstOrNull { it.description == targetPlatformName }
                              ?: TargetPlatformKind.Jvm[JvmTarget.DEFAULT]
 
@@ -57,6 +60,14 @@ private fun readV1Config(element: Element): KotlinFacetSettings {
             is K2JSCompilerArguments -> jsArgumentsElement?.let { XmlSerializer.deserializeInto(compilerArguments, it) }
         }
 
+        if (languageLevel != null) {
+            compilerArguments.languageVersion = languageLevel
+        }
+
+        if (apiLevel != null) {
+            compilerArguments.apiVersion = apiLevel
+        }
+
         if (useProjectSettings != null) {
             this.useProjectSettings = useProjectSettings
         }