Disable AllowResultInReturnType feature

#KT-40843

compiler/testData/cli/jvm/resultInReturnTypeWithEnabledInlineClasses.out

@@ -1 +1,4 @@
-OK
+compiler/testData/cli/jvm/resultInReturnType.kt:1:5: error: 'kotlin.Result' cannot be used as a return type
+fun foo() = Result.success(42)
+    ^
+COMPILATION_ERROR

compiler/testData/cli/jvm/resultInReturnTypeWithEnabledInlineClassesXX.out

@@ -7,4 +7,7 @@ This mode is not recommended for production use,
 as no stability/compatibility guarantees are given on
 compiler or generated code. Use it at your own risk!
 
-OK
+compiler/testData/cli/jvm/resultInReturnType.kt:1:5: error: 'kotlin.Result' cannot be used as a return type
+fun foo() = Result.success(42)
+    ^
+COMPILATION_ERROR

compiler/testData/diagnostics/testsWithStdLib/annotations/annotationApplicability/jvmNameOnMangledNames.kt

@@ -16,15 +16,15 @@ fun baz(r: Result<Int>) {}
 fun returnsInlineClass() = Foo(1)
 
 @JvmName("test")
-fun returnsKotlinResult(a: Result<Int>): Result<Int> = a
+fun returnsKotlinResult(a: Result<Int>): <!RESULT_CLASS_IN_RETURN_TYPE!>Result<Int><!> = a
 
 class C {
     <!INAPPLICABLE_JVM_NAME!>@JvmName("test")<!>
     fun returnsInlineClass() = Foo(1)
 
     <!INAPPLICABLE_JVM_NAME!>@JvmName("test")<!>
-    fun returnsKotlinResult(a: Result<Int>): Result<Int> = a
+    fun returnsKotlinResult(a: Result<Int>): <!RESULT_CLASS_IN_RETURN_TYPE!>Result<Int><!> = a
 }
 
 <!INAPPLICABLE_JVM_NAME!>@JvmName("extensionFun")<!>
-fun Foo.extensionFun() {}
+fun Foo.extensionFun() {}

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -115,7 +115,7 @@ enum class LanguageFeature(
     ProperFinally(KOTLIN_1_4, kind = BUG_FIX),
     AllowAssigningArrayElementsToVarargsInNamedFormForFunctions(KOTLIN_1_4),
     AllowNullOperatorsForResult(KOTLIN_1_4),
-    AllowResultInReturnType(KOTLIN_1_4),
+    AllowResultInReturnType(KOTLIN_1_4, defaultState = State.DISABLED),
     PreferJavaFieldOverload(KOTLIN_1_4),
     AllowContractsForNonOverridableMembers(KOTLIN_1_4),
     AllowReifiedGenericsInContracts(KOTLIN_1_4),