Do not intercept output from MSBuild

[yecril71pl]

Do not intercept output from MSBuild
Fixes #1738

Class MsBuildProjectContextBuilder is not being tested. Moreover, we have no control over what MSBuild writes to standard output, so there is nothing to assert.

[deepchoudhery]

We can discuss here but I tend to prefer the standard output being redirected. Seeing the build output provides more clarity to VS and command line users as to the scaffolding process. It is not particularly verbose and can highlight warnings that may cause scaffolding to fail. Helps users and me alike to solve any issues with scaffolders and especially custom scaffolders. That's just my take on it.
Let me know how you feel @yecril71pl.

[yecril71pl]

Seeing the build output

You can see the build output in two ways:

1. Just let the subprocess do its thing.
2. Intercept all output from the subprocess and present it ourselves.

This change switches from mode 2 to mode 1. Mode 2 makes sense when we do something to the output, like code page conversion, injecting time stamps, teeing into a secondary logger or whatever. We do not do any of these things, so I would rather prefer it raw, if possible.