Missing end of groups in documentation comments

There are several places in `jerry-core/ecma` directory where the end of documentation groups are missing. For example:
- ecma-boolean-object.cpp
- ecma-number-object.cpp
### Task

We should check all files for this and fix this style issue in one commit.
### Solution

Insert to the end of files:

``` C++
/**
 * @}
 * @}
 */
```
