I am supposed to do an offline installation of vstest.console.exe in the folder path as follows: C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\CommonExtensions\Microsoft\TestWindow
I have tried using offline packages such as vs_testagent.exe and vs_testcontroller.exe according to the following link: https://learn.microsoft.com/en-us/visualstudio/install/create-a-network-installation-of-visual-studio. However, these packages do not contain vstest.console.exe.
I am also unable to do a full installation of VS2017 due to space issues. Do anyone have any suggestions? Thanks.

You are looking for "Build Tools for Visual Studio" (Microsoft login required). It will give you an installer "vs_BuildTools.exe", which will install by default the build tools in:
(by default)
Two versions of vstest console were installed when I ran it:
I do not know why, nor how they are different. I use the first one.