[stdlib] Set AV to 2.0, LV to 1.9 for main compilations, build tests with K2

libraries/stdlib/jvm-minimal-for-test/build.gradle.kts

@@ -55,6 +55,8 @@ tasks.compileKotlin {
         "kotlin/enums/EnumEntries.kt"
     ).map { copySources.get().destinationDir.resolve(it) }
     kotlinOptions {
+        languageVersion = "1.9"
+        apiVersion = "2.0"
         freeCompilerArgs += listOf(
             "-Xallow-kotlin-package",
             "-Xexpect-actual-classes",
@@ -62,6 +64,7 @@ tasks.compileKotlin {
             "-opt-in=kotlin.RequiresOptIn",
             "-opt-in=kotlin.contracts.ExperimentalContracts",
             "-opt-in=kotlin.ExperimentalMultiplatform",
+            "-Xsuppress-api-version-greater-than-language-version-error",
         )
         moduleName = "kotlin-stdlib"
     }