Revert "link executables dynamically to speed up linking (haskell#4423)"

This reverts commit 2df8775.

Author: fendor

cabal.project

@@ -17,12 +17,6 @@ benchmarks: True
 
 write-ghc-environment-files: never
 
--- Link executables dynamically so the linker doesn't produce test
--- executables of ~150MB each and works lightning fast at that too
--- Disabled on Windows
-if(!os(windows))
-  executable-dynamic: True
-
 -- Many of our tests only work single-threaded, and the only way to
 -- ensure tasty runs everything purely single-threaded is to pass
 -- this at the top-level