Add ghc-prim to build-depends for LPGF testsuite

gf.cabal

@@ -583,6 +583,7 @@ test-suite lpgf
     containers >= 0.5.7 && < 0.7,
     directory >= 1.3.0 && < 1.4,
     filepath >= 1.4.1 && < 1.5,
+    ghc-prim >= 0.5.0 && < 0.7,
     hashable >= 1.2.6 && < 1.4,
     haskeline >= 0.7.3 && < 0.9,
     json >= 0.9.1 && < 0.11,