Add another Path test

This adds a new test that verifies the output of `compiler-store-path`
when the store-dir is explicitly configured.

Author: sgillespie

cabal-testsuite/PackageTests/Path/Compiler/cabal.out

@@ -10,3 +10,8 @@ compiler-flavour: ghc
 compiler-id: ghc-<GHCVER>
 compiler-path: <GHCPATH>
 compiler-store-path: <ROOT>/cabal.dist/home/.cabal/store/ghc-<GHCVER>
+# cabal path
+compiler-flavour: ghc
+compiler-id: ghc-<GHCVER>
+compiler-path: <GHCPATH>
+compiler-store-path: fake-dir/ghc-<GHCVER>

cabal-testsuite/PackageTests/Path/Compiler/cabal.test.hs

@@ -5,3 +5,4 @@ main = cabalTest $ do
   void $ cabal "path" ["-z", "--output-format=key-value", "--compiler-info"]
   void $ cabal "path" ["-z", "--output-format=json", "--compiler-info"]
   void $ cabal "path" ["-z", "--compiler-info"]
+  void $ cabalG ["--store-dir=fake-dir"] "path" ["-z", "--compiler-info"]