Fix run-test.sh to find all test projects

run-test.sh is currently looking for test projects of the form
src/**/tests/*.csproj, but some of our projects are nested a level down
from that, e.g. src/**/tests/something/*.csproj.

Author: stephentoub

run-test.sh

@@ -269,7 +269,7 @@ create_test_overlay
 TestsFailed=0
 numberOfProcesses=0
 maxProcesses=$(($(getconf _NPROCESSORS_ONLN)+1))
-for file in src/**/tests/*.Tests.csproj
+for file in src/**/tests/**/*.Tests.csproj
 do
   runtest $file &
   pids="$pids $!"