### Description
Hi. The code below does not have the same output as other engines (e.g., V8 in Google Chrome,SpiderMonkey in Firefox,chakra in Edge,quickjs,jerryscript). 

#### JerryScript revision
3.0.0

#### Build platform
ubuntu20.04

#### Test case
`var regex=/(?:(\s)((?:\w*\1)){1,8}){2,5}/`
`regex.exec(" A B  C D E F G H   I ")`

#### Output
 `A B  C D E F G H   I , ,I `

#### Expected behavior
`A B  C D E F G H   ,  ,  `

Regex bug
This is a GitHub Issue
repo:jerryscript
owner:jerryscript-project
Title : Regex bug
Issue date:

--- start body ---
### Description
Hi. The code below does not have the same output as other engines (e.g., V8 in Google Chrome,SpiderMonkey in Firefox,chakra in Edge,quickjs,jerryscript). 

#### JerryScript revision
3.0.0

#### Build platform
ubuntu20.04

#### Test case
`var regex=/(?:(\s)((?:\w*\1)){1,8}){2,5}/`
`regex.exec(" A B  C D E F G H   I ")`

#### Output
 `A B  C D E F G H   I , ,I `

#### Expected behavior
`A B  C D E F G H   ,  ,  `

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