[sre] Throw a TLE if a generic inst is used before the gtd is created.

[sre] Throw a TLE if a generic inst is used before the gtd is created.

This can happen if TypeBuilders are used to construct something like
  class S<T> {
    ...
  }
  class R {
    public S<int> SI;
  }

And then CreateType() is called for R and GetField("SI") is called on
  the result before CreateType() is called on the builder for S.