Drop usages of CompilerArguments::useExperimental

jps/jps-common/test/CompilerArgumentsContentProspectorTest.kt

@@ -120,7 +120,6 @@ class CompilerArgumentsContentProspectorTest {
         private val commonCompilerArgumentsArrayProperties = listOf(
             CommonCompilerArguments::pluginOptions,
             CommonCompilerArguments::pluginClasspaths,
-            CommonCompilerArguments::useExperimental,
             CommonCompilerArguments::optIn,
             CommonCompilerArguments::commonSources,
             CommonCompilerArguments::disablePhases,

js/js.tests/test/org/jetbrains/kotlin/benchmarks/GenerateIrRuntime.kt

@@ -306,7 +306,7 @@ class GenerateIrRuntime {
             irOnly = true
             irModuleName = "kotlin"
             allowKotlinPackage = true
-            useExperimental = arrayOf("kotlin.contracts.ExperimentalContracts", "kotlin.Experimental", "kotlin.ExperimentalMultiplatform")
+            optIn = arrayOf("kotlin.contracts.ExperimentalContracts", "kotlin.Experimental", "kotlin.ExperimentalMultiplatform")
             allowResultReturnType = true
             multiPlatform = true
             languageVersion = "1.4"