Build: remove obsolete compiler arguments

These compiler arguments enable features which are enabled by default in
the current Kotlin anyway.

The only exception is in :compiler:cli which uses an old language
version.

libraries/stdlib/common/build.gradle

@@ -43,9 +43,7 @@ compileKotlinCommon {
                 "-Xopt-in=kotlin.RequiresOptIn",
                 "-Xopt-in=kotlin.ExperimentalMultiplatform",
                 "-Xopt-in=kotlin.contracts.ExperimentalContracts",
-                "-Xinline-classes",
                 "-Xallow-kotlin-package",
-                "-Xallow-result-return-type"
         ]
     }
 }