perf: split GHC.Hs.Instances for parallel compilation (#18254)

Split the monolithic GHC.Hs.Instances module (344 Data instances, 14MB
object file) into 5 parallel-compilable sub-modules:

  - GHC.Hs.Instances.Common      - phase-independent instances
  - GHC.Hs.Instances.Transitions - LR types spanning multiple phases
  - GHC.Hs.Instances.Parsed      - GhcPs instances only
  - GHC.Hs.Instances.Renamed     - GhcRn instances only
  - GHC.Hs.Instances.Typechecked - GhcTc instances only

The wrapper module GHC.Hs.Instances re-exports all sub-modules for
backward compatibility.

Additionally, all Instance modules are now excluded from stage1 builds
(via -interpreter flag) since Data instances are only needed at runtime
for Template Haskell and GHCi, not for compilation.

Benefits:
- Stage1: Saves ~14MB object file + compile time
- Stage2: 5 modules can compile in parallel instead of 1 serial

See #9557 for why these use -O0, #18254 for the parallelism issue.

Author: angerman

compiler/GHC/Hs.hs

@@ -10,6 +10,7 @@ therefore, is almost nothing but re-exporting.
 -}
 
 {-# OPTIONS_GHC -Wno-orphans    #-} -- Outputable
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE StandaloneDeriving #-}
 {-# LANGUAGE FlexibleContexts #-}
@@ -54,7 +55,10 @@ import GHC.Hs.Pat
 import GHC.Hs.Type
 import GHC.Hs.Utils
 import GHC.Hs.Doc
+
+#if defined(HAVE_INTERPRETER)
 import GHC.Hs.Instances () -- For Data instances
+#endif
 
 -- others:
 import GHC.Utils.Outputable