Fix incremental build of mscordaccore (dotnet/coreclr#9982)

Fix incremental build of mscordaccore (dotnet/coreclr#9982)

* Fix incremental build of mscordaccore

This change sets up proper dependency for the mscordaccore build and stops
using PRE_LINK command which is executed always.
The way it solves the problem is that it creates an object library from the
mscordac.cpp and then lets the mscordaccore.exp be generated from that object
and finally use both that object library and the mscordaccore.exp while building
mscordaccore.

Commit migrated from https://github.com/dotnet/coreclr/commit/be4ab599db716c105956befffc39a303682ad801