[TASK] Refactor unit test to cover stdWrap_numberFormat

- Refactor the unit test of numberFormat.
- Refactor the unit test of stdWrap_numberFormat to show it delegates to
  numberFormat.

Releases: master
Resolves: #76775
Change-Id: I42b2c1f4daa035c56f6fdd836a7fa26fcbe52fa6
Reviewed-on: https://review.typo3.org/48678


Tested-by: Bamboo TYPO3com <info@typo3.com>
Reviewed-by: Susanne Moog <typo3@susannemoog.de>
Tested-by: Susanne Moog <typo3@susannemoog.de>