Add option to disable normalize embeddings after after calculating emphasis.

[hako-mikan]

Description

In SDXL, there have been reports of artifacts occurring when combining prompts or using long prompts. I have discovered the cause of this phenomenon. It is the normalization that occurs after the calculation of emphasis. During this normalization, artifacts arise due to division by values close to zero and the inversion of signs. This normalization process dates back to the SD1.X era, where it seems to work well. However, in certain models of XL, it appears to have the opposite effect. Therefore, I will add an option to toggle this normalization on and off.
The detailed explanation can be found here or here(Japanese)

Checklist:

• I have read contributing wiki page
• I have performed a self-review of my own code
• My code follows the style guidelines
• My code passes tests