rework CacheWriter writeAll() and deleteAll() to permit partial success

The following might do the trick.  Note conversion of the method to an instance method and removal of the type parameter <K>.

```java
  private void collectSuccessesAndFailures(BulkCacheWriterException bcwe, Set<K> successes, Map<K, Exception> failures) {
    Collections.checkedSet(successes, this.runtimeConfiguration.getKeyType()).addAll((Collection<K>)bcwe.getSuccesses());
    Collections.checkedMap(failures, this.runtimeConfiguration.getKeyType(), Exception.class).putAll((Map<K, Exception>)bcwe.getFailures());
  }
```