Revert "[FE 1.0] Deprecate declaration of expect and actual in the same module"

This reverts commit b09561c3c3.

It was decided to postpone this warning till 1.9
This is needed to provide proper IDE support

^KT-40904 Open
^KT-55177 Open

compiler/testData/diagnostics/tests/multiplatform/expectAndActualInSameModule.fir.kt

@@ -1,17 +0,0 @@
-// ISSUE: KT-40904, KT-55177
-
-expect class Foo {
-    fun memberFun()
-    val memberProp: Int
-}
-actual class Foo {
-    <!ACTUAL_WITHOUT_EXPECT!>actual fun memberFun() {}<!>
-    <!ACTUAL_WITHOUT_EXPECT!>actual val memberProp: Int = 10<!>
-}
-
-expect fun foo()
-<!ACTUAL_WITHOUT_EXPECT!>actual fun foo() {}<!>
-
-expect val x: String
-<!ACTUAL_WITHOUT_EXPECT!>actual val x: String
-    get() = "hello"<!>

compiler/testData/diagnostics/tests/multiplatform/expectAndActualInSameModule.kt

@@ -1,17 +0,0 @@
-// ISSUE: KT-40904, KT-55177
-
-expect <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>class Foo<!> {
-    fun memberFun()
-    val memberProp: Int
-}
-actual <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>class Foo<!> {
-    actual fun memberFun() {}
-    actual val memberProp: Int = 10
-}
-
-expect fun <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>foo<!>()
-actual fun <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>foo<!>() {}
-
-expect val <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>x<!>: String
-actual val <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>x<!>: String
-    get() = "hello"

compiler/testData/diagnostics/tests/multiplatform/expectAndActualInSameModule.txt

@@ -1,14 +0,0 @@
-package
-
-public actual val x: kotlin.String
-public actual fun foo(): kotlin.Unit
-
-public final actual class Foo {
-    public constructor Foo()
-    public actual final val memberProp: kotlin.Int = 10
-    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public final actual fun memberFun(): kotlin.Unit
-    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
-}
-