Documentation: Add CoreCLR binary folder to test results (dotnet/coreclr#5084)

Documentation: Add CoreCLR binary folder to test results (dotnet/coreclr#5084)

When we get the test result with ./coreclr/tests/runtest.sh,
it is difficult to classify the build mode that we used after some days.

Let's add information of the CoreCLR binary folder in order to
know easily the build mode between debug-build and release-build mode.

Signed-off-by: Geunsik Lim <geunsik.lim@samsung.com>
Commit migrated from https://github.com/dotnet/coreclr/commit/c6ac87f88f533cea120bbbd2c273a2e78cc2ea1f