KE2: Use the right language version

With this, if I make the testsuite driver use 1.7, then the test code

sealed interface ReadResult
data class Number(val number: Int) : ReadResult
data class Text(val text: String) : ReadResult
data object EndOfFile : ReadResult

makes the extractor print

=== Diagnostics
--- Diagnostic:
WRONG_MODIFIER_TARGET
ERROR
Modifier 'data' is not applicable to 'standalone object'.
Location(startLine=5, startColumn=1, endLine=5, endColumn=4)
--- End diagnostics

java/kotlin-extractor2/src/main/kotlin/KotlinExtractor.kt

@@ -28,6 +28,7 @@ import org.jetbrains.kotlin.analysis.project.structure.builder.buildKtSdkModule
 import org.jetbrains.kotlin.analysis.project.structure.builder.buildKtSourceModule
 import org.jetbrains.kotlin.cli.common.arguments.parseCommandLineArguments
 import org.jetbrains.kotlin.cli.common.arguments.K2JVMCompilerArguments
+import org.jetbrains.kotlin.cli.common.messages.MessageCollector
 import org.jetbrains.kotlin.platform.jvm.JvmPlatforms
 import org.jetbrains.kotlin.psi.*
 
@@ -181,6 +182,9 @@ fun doAnalysis(
     lateinit var sourceModule: KaSourceModule
     val k2args: K2JVMCompilerArguments = parseCommandLineArguments(args.toList())
 
+    // TODO: Collect the messages, and log them?
+    val ourLanguageVersionSettings = k2args.toLanguageVersionSettings(MessageCollector.NONE)
+
     val session = buildStandaloneAnalysisAPISession {
         registerProjectService(KotlinLifetimeTokenProvider::class.java, KotlinAlwaysAccessibleLifetimeTokenProvider())
 
@@ -210,6 +214,7 @@ fun doAnalysis(
             )
             sourceModule = addModule(
                 buildKtSourceModule {
+                    languageVersionSettings = ourLanguageVersionSettings
                     addSourceRoots(k2args.freeArgs.map { Paths.get(it) })
                     addRegularDependency(sdk)
                     addRegularDependency(lib)