Comparison of function 'normalize_environment' equal to NULL is always false.

Linked PRs

• gh-128217: Fix incorrect result verification. #128219
• gh-128217: Fix incorrect result verification. #128220
• [3.13] gh-128217: Validate the normalized_environment variable instead of the similarly named function (GH-128220) #128221
• [3.12] gh-128217: Validate the normalized_environment variable instead of the similarly named function (GH-128220) #128222