move psutil into requirements.txt and remove from travis/appveyor's setup files

Author: bdbaddog

.appveyor/install.bat

@@ -3,7 +3,7 @@ for /F "tokens=*" %%g in ('C:\\%WINPYTHON%\\python.exe -c "import sys; print(sys
 REM use mingw 32 bit until #3291 is resolved
 set PATH=C:\\%WINPYTHON%;C:\\%WINPYTHON%\\Scripts;C:\\ProgramData\\chocolatey\\bin;C:\\MinGW\\bin;C:\\MinGW\\msys\\1.0\\bin;C:\\cygwin\\bin;C:\\msys64\\usr\\bin;C:\\msys64\\mingw64\\bin;%PATH%
 C:\\%WINPYTHON%\\python.exe -m pip install -U --progress-bar off pip setuptools wheel
-C:\\%WINPYTHON%\\python.exe -m pip install -U --progress-bar off coverage codecov psutil
+C:\\%WINPYTHON%\\python.exe -m pip install -U --progress-bar off coverage codecov
 set STATIC_DEPS=true & C:\\%WINPYTHON%\\python.exe -m pip install -U --progress-bar off lxml
 C:\\%WINPYTHON%\\python.exe -m pip install -U --progress-bar off -r requirements.txt
 REM install 3rd party tools to test with

.travis/install.sh

@@ -57,7 +57,6 @@ else
         pip install git+https://github.com/cython/[email protected]
         pip install git+https://github.com/lxml/lxml.git
     fi
-    pip install psutil
 
 #    sudo wget http://master.dl.sourceforge.net/project/d-apt/files/d-apt.list -O /etc/apt/sources.list.d/d-apt.list
 #    wget -qO - https://dlang.org/d-keyring.gpg | sudo apt-key add -

requirements.txt

@@ -9,4 +9,7 @@ sphinx<3.5.0
 sphinx_rtd_theme
 lxml==4.6.3
 rst2pdf
-ninja
+ninja
+
+# Needed for test/Parallel/failed-build/failed-build.py
+psutil