Update testing-with-corefx.md
authorCarol Eidt <carol.eidt@microsoft.com>
Mon, 7 Nov 2016 21:47:52 +0000 (13:47 -0800)
committerGitHub <noreply@github.com>
Mon, 7 Nov 2016 21:47:52 +0000 (13:47 -0800)
commitfd402e530b504933cbcef08408bf76a666a54a2f
tree05da6962c5e47d2c2914d4e09379c4f702e1e087
parent5c653c193336fd8d1c3e88eabb64614612838f77
Update testing-with-corefx.md

Clarify the way the `BUILDTOOLS_OVERRIDE_RUNTIME` option is passed.
Documentation/building/testing-with-corefx.md