nori analyzer issue with trailing space [LUCENE-8532]

We can reproduce it from Elasticsearch.

When we run the following command:

`GET _analyze`

{ 

"analyzer": "nori",

  "text": "공단시"

``}

It returns the following as expected:

{
  "tokens": [
   

{       "token": "공단",       "start_offset": 0,       "end_offset": 2,       "type": "word",       "position": 0     }

,
   

{       "token": "시",       "start_offset": 2,       "end_offset": 3,       "type": "word",       "position": 1     }

  ]
}

But if we run with "공단시 " (with a trailing space)

GET _analyze

{   "analyzer": "nori",   "text": "공단시 " }

It returns

{
  "tokens": [
   

{       "token": "공단",       "start_offset": 0,       "end_offset": 2,       "type": "word",       "position": 0     }

,
   

{       **"token": "씨",**       "start_offset": 2,       "end_offset": 3,       "type": "word",       "position": 1     }

  ]
}

The second token should be "시" instead of  "씨".

---
Migrated from [LUCENE-8532](https://issues.apache.org/jira/browse/LUCENE-8532) by Kiju Kim (@kiju98)
Environment:
```
Elasticsearch version: Version: Version: 6.4.2, Build: default/tar/04711c2/2018-09-26T13:34:09.098244Z, JVM: 1.8.0_131

Plugins installed: [analysis-nori]

JVM version:
java version "1.8.0_131"
Java(TM) SE Runtime Environment (build 1.8.0_131-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.131-b11, mixed mode)

OS version: Darwin Kijuui-MacBook-Pro.local 17.7.0 Darwin Kernel Version 17.7.0: Thu Jun 21 22:53:14 PDT 2018; root:xnu-4570.71.2~1/RELEASE_X86_64 x86_64
```

Attachments: [LUCENE-8532.patch](https://apache.github.io/lucene-jira-archive/attachments/LUCENE-8532/LUCENE-8532.patch)

Reproduce the issue with the Elasticsearch _analyze command using the nori analyzer, comparing input with and without the trailing space. Review the attached LUCENE-8532.patch and the analyzer behavior involved in tokenizing the final syllable. Done means the trailing-space input produces the token "시" rather than "씨" while preserving the existing token offsets.

Written by the indexing model from the issue text.