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/endorsedLibraries/kotlinx.cli/build.gradle.kts

@@ -46,7 +46,7 @@ kotlin {
 
             compilations.all {
                 kotlinOptions {
-                    freeCompilerArgs = listOf("-opt-in=kotlinx.cli.ExperimentalCli", "-opt-in=kotlin.RequiresOptIn")
+                    freeCompilerArgs += listOf("-opt-in=kotlinx.cli.ExperimentalCli")
                     suppressWarnings = true
                 }
             }