[kotlinx-metadata-klib] Drop dependency on descriptors

It's unneeded since all used declarations moved to
:core:compiler.common.

libraries/kotlinx-metadata/klib/build.gradle.kts

@@ -26,8 +26,6 @@ dependencies {
     compile(kotlinStdlib())
     shadows(project(":kotlinx-metadata"))
     shadows(project(":core:compiler.common"))
-    // TODO: Get rid of this heavyweight dependency.
-    shadows(project(":core:descriptors"))
     shadows(project(":core:metadata"))
     shadows(project(":core:deserialization"))
     shadows(project(":compiler:serialization"))