Fix linux builds.

Remove automatically inserted
EnsureNuGetPackageBuildImports target that uses
dynamic PropertyGroups which mono's xbuild does not
have. It's not necessary because the import of
NuGet.targets will fail if it's not present.
Fix platform and bin folders in global run_tests scripts.
Add oradbsc to global run_tests scripts.
Set oradbsc run_tests.sh as executable.