no-placeholder compact number patterns throw IllegalArgumentException

Upcoming CLDR 38 will have compact number patterns without a placeholder:

https://unicode-org.atlassian.net/browse/CLDR-11045

Current JDK will throw an exception for such pattern as:

```
java.lang.IllegalArgumentException: Invalid pattern [Kun]: all patterns must include digit placement 0s
at java.base/java.text.CompactNumberFormat.applyPattern(CompactNumberFormat.java:1405)
at java.base/java.text.CompactNumberFormat.lambda$processCompactPatterns$0(CompactNumberFormat.java:1167)
at java.base/java.util.regex.Matcher$1MatchResultIterator.forEachRemaining(Matcher.java:1358)
at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:658)
at java.base/java.text.CompactNumberFormat.processCompactPatterns(CompactNumberFormat.java:1167)
at java.base/java.text.CompactNumberFormat.<init>(CompactNumberFormat.java:464)
```