Add necessary optIn arguments to FIR full pipeline tests

compiler/fir/modularized-tests/tests/org/jetbrains/kotlin/fir/FullPipelineModularizedTest.kt

@@ -16,6 +16,12 @@ class FullPipelineModularizedTest : AbstractFullPipelineModularizedTest() {
         args.useIR = true
         args.apiVersion = LANGUAGE_VERSION
         args.jvmDefault = "compatibility"
+        args.optIn = arrayOf(
+            "kotlin.RequiresOptIn",
+            "kotlin.contracts.ExperimentalContracts",
+            "kotlin.io.path.ExperimentalPathApi",
+            "org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI"
+        )
     }
 
     fun testTotalKotlin() {