Bump `base` version to 4.8.0.0 for real

This commit updates several submodules in order to bump
the upper bounds on `base` of most boot packages

Moreover, this updates some of the test-suite cases which have
version numbers hardcoded within.

However, I'm not sure if this commit didn't introduce the following
two test-failures

   ghc-api  T8628 [bad stdout] (normal)
   ghc-api  T8639_api [bad stdout] (normal)

This needs investigation