[Commonizer] AbstractCommonizationFromSourcesTest remove assertions on commonized leaf/platform libraries

Those assertions are not necessary anymore, since the commonizer is not
expected to produce any new "actuals" per given expect.
The IDE is supposed to analyze leaf source sets against the original
platform libraries.

native/commonizer/testData/callableMemberCommonization/openCallableMemberInInterface/commonized/js/package_root.kt

@@ -1,5 +0,0 @@
-actual interface Interface {
-    actual fun openFun() = Unit
-    fun openFunWithOtherParams(param: Int) = Unit
-    fun openInJs_abstractInJvm() = Unit
-}

native/commonizer/testData/callableMemberCommonization/openCallableMemberInInterface/commonized/jvm/package_root.kt

@@ -1,5 +0,0 @@
-actual interface Interface {
-    actual fun openFun() = Unit
-    fun openFunWithOtherParams(param: Double) = Unit
-    fun openInJs_abstractInJvm()
-}