Add ${PYTHON_EXECUTABLE} for "Generating doctests" (#4496)
Add ${PYTHON_EXECUTABLE} for "Generating doctests" (#4496)

On win32, the ${PYTHON_EXECUTABLE} should be specified, otherwise the python script
can not be executed properly.

JerryScript-DCO-1.0-Signed-off-by: Yonggang Luo luoyonggang@gmail.com
robertsipka/jerryscript,jerryscript-project/jerryscript,zherczeg/jerryscript,robertsipka/jerryscript,jerryscript-project/jerryscript,jerryscript-project/jerryscript,robertsipka/jerryscript,dbatyai/jerryscript,zherczeg/jerryscript,robertsipka/jerryscript,bzsolt/jerryscript,zherczeg/jerryscript,robertsipka/jerryscript,jerryscript-project/jerryscript,bzsolt/jerryscript,jerryscript-project/jerryscript,bzsolt/jerryscript,bzsolt/jerryscript,dbatyai/jerryscript,dbatyai/jerryscript,dbatyai/jerryscript,robertsipka/jerryscript,zherczeg/jerryscript,dbatyai/jerryscript,bzsolt/jerryscript,zherczeg/jerryscript