Drop MetadataComparisonTest & drop build-tools -> util-klib dependency

Review: https://jetbrains.team/p/kt/reviews/8360

MetadataComparisonTest was the only one in build-tools module who
depended on util-klib, that's why we can drop build-tools -> util-klib
dependency

MetadataComparisonTest is no longer needed, that's why we can drop it.

The dependency drop is a one step forward in dropping
`kotlin.srcDir("../compiler/util-klib/src")` line in
`buildSrc/build.gradle.kts`. Adding source roots in `buildSrc` is hacky
and can lead to frustrations (e.g. KT-55874). That's why it's desirable
to drop buildSrc -> util-klib hacky dependency.

Unfortunatelly, I couldn't drop buildSrc -> util-klib dependency,
because:
1. buildSrc depends on kotlin-native/shared/src/library/kotlin +
   buildSrc depends on kotlin-native/tools/kotlin-native-gradle-plugin +
   maybe smth else
2. kotlin-native/shared/src/library/kotlin depends on util-klib +
   kotlin-native/tools/kotlin-native-gradle-plugin depends on util-klib +
   maybe smth else

compiler/util-klib/src/org/jetbrains/kotlin/library/KotlinLibrary.kt

@@ -20,6 +20,10 @@ const val KLIB_PROPERTY_CONTAINS_ERROR_CODE = "contains_error_code"
 // Native-specific:
 const val KLIB_PROPERTY_INTEROP = "interop"
 const val KLIB_PROPERTY_EXPORT_FORWARD_DECLARATIONS = "exportForwardDeclarations"
+
+/**
+ * Copy-pasted to `kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/Utils.kt`
+ */
 const val KLIB_PROPERTY_NATIVE_TARGETS = "native_targets"
 
 // Commonizer-specific: