pip install --target --upgrade removes existing packages scripts

Environment

• pip version:20.0.2
• Python version:3.8.2
• OS:MacOS

Description pip with -t removed other file in target bin folder

Expected behavior

when install package ipython should not remove package pylint bin files

How to Reproduce

mkdir test
pip install -t test pylint
ls test/bin/
epylint  isort  pylint  pyreverse  symilar

pip install -U -t test ipython
ls test/bin/
easy_install  easy_install-3.8  iptest  iptest3  ipython  ipython3  pygmentize

Output

After install ipython, pylint is deleted.