Do not reset freeCompilerArgs for some kotlin-native modules

Otherwise common compiler arguments which are set for all modules in the
project in `buildSrc/src/main/kotlin/common-configuration.gradle.kts`
are not applied. The most interesting of those are `-Xuse-k2` (if K2 is
enabled) and `-Xjvm-default=all`.

kotlin-native/utilities/basic-utils/build.gradle.kts

@@ -15,7 +15,7 @@ plugins {
 
 tasks.named<KotlinCompile>("compileKotlin") {
     kotlinOptions {
-        freeCompilerArgs = listOf("-Xskip-metadata-version-check")
+        freeCompilerArgs += listOf("-Xskip-metadata-version-check")
     }
 }