Runtimes: properly link in `swiftrtT?.obj` on Windows
`swiftrtT.obj` should be used for statically linking the standard
library (or within the standard library itself). For the other modules,
we need to differentiate between `swiftrt.obj` and `swiftrtT.obj`. This
fixes that oversight. This was not caught by the CI builds as we do not
currently build both the static and dynamic variants of the new
runtimes.
