Add KmVersionRequirementKind.UNKNOWN

for cases when the version requirement cannot be read correctly (missing from the table).

It usually happens when we read the inner class' old metadata, which stored everything
in the outer class' table.

Fixes #KT-60870


Merge-request: KT-MR-13337
Merged-by: Leonid Startsev <leonid.startsev@jetbrains.com>

libraries/tools/kotlinp/src/org/jetbrains/kotlin/kotlinp/printers.kt

@@ -322,6 +322,7 @@ private fun printVersionRequirement(versionRequirement: KmVersionRequirement): S
                 KmVersionRequirementVersionKind.LANGUAGE_VERSION -> "language version"
                 KmVersionRequirementVersionKind.COMPILER_VERSION -> "compiler version"
                 KmVersionRequirementVersionKind.API_VERSION -> "API version"
+                KmVersionRequirementVersionKind.UNKNOWN -> "unknown requirement"
             }
         ).append(" ").append(version)