Test that new-sdist gets globbing right

The code does the right thing, but it's slightly fragile since it
depends on directory switching, so make sure it stays right.

cabal-testsuite/PackageTests/NewSdist/Globbing/a/Main.hs

+main = putStrLn "Main.hs"

cabal-testsuite/PackageTests/NewSdist/Globbing/a/a.cabal

+cabal-version: 2.2
+name: a
+version: 1
+extra-doc-files:
+  doc/*.html
+
+executable a
+  default-language: Haskell2010
+  main-is: Main.hs

cabal-testsuite/PackageTests/NewSdist/Globbing/a/doc/index.html

+index.html

cabal-testsuite/PackageTests/NewSdist/Globbing/cabal.out

+# cabal new-sdist
+a/Main.hs
+a/a.cabal
+a/doc/index.html

cabal-testsuite/PackageTests/NewSdist/Globbing/cabal.project

+packages:
+  a/

cabal-testsuite/PackageTests/NewSdist/Globbing/cabal.test.hs

+import Test.Cabal.Prelude
+main = cabalTest $ withSourceCopy $ do
+  cabal "new-sdist" ["a", "--list-only"]
+