Remove IncDecOperatorsInExpectClass test

It is incorrect because has expect and actual in same module,
which results in ACTUAL_WITHOUT_EXPECT reported in FIR.
But there is already same test
`multiplatform/incDecOperatorsInExpectClass.kt`, so there is no need
to fix and maintain test `IncDecOperatorsInExpectClass`.

^KT-60075 Fixed

compiler/testData/diagnostics/tests/IncDecOperatorsInExpectClass.fir.kt

@@ -1,13 +0,0 @@
-// In FIR, declaring the same `expect` and `actual` classes in one compiler module is not possible (see KT-55177). Hence the `.fir.kt` test
-// expects a diagnostic here. The multi-module test corresponding to this test is called: `multiplatform/incDecOperatorsInExpectClass.kt`.
-
-// !LANGUAGE: +MultiPlatformProjects
-// SKIP_TXT
-// Issue: KT-49714
-
-expect class Counter {
-    operator fun inc(): Counter
-    operator fun dec(): Counter
-}
-
-actual typealias <!ACTUAL_WITHOUT_EXPECT!>Counter<!> = Int

compiler/testData/diagnostics/tests/IncDecOperatorsInExpectClass.kt

@@ -1,13 +0,0 @@
-// In FIR, declaring the same `expect` and `actual` classes in one compiler module is not possible (see KT-55177). Hence the `.fir.kt` test
-// expects a diagnostic here. The multi-module test corresponding to this test is called: `multiplatform/incDecOperatorsInExpectClass.kt`.
-
-// !LANGUAGE: +MultiPlatformProjects
-// SKIP_TXT
-// Issue: KT-49714
-
-expect <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>class Counter<!> {
-    operator fun inc(): Counter
-    operator fun dec(): Counter
-}
-
-actual typealias <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>Counter<!> = Int