v2-haddock should fail when v2-build fails

cabal-testsuite/PackageTests/NewHaddock/Fails/Example.hs

+module Example where
+
+import Prelude
+
+example :: Int
+example = False

cabal-testsuite/PackageTests/NewHaddock/Fails/cabal.out

+# cabal v2-build
+Resolving dependencies...
+Build profile: -w ghc-<GHCVER> -O1
+In order, the following will be built:
+ - example-1.0 (lib) (first run)
+Configuring library for example-1.0..
+Preprocessing library for example-1.0..
+Building library for example-1.0..
+# cabal v2-haddock
+Build profile: -w ghc-<GHCVER> -O1
+In order, the following will be built:
+ - example-1.0 (lib) (first run)
+Preprocessing library for example-1.0..
+Running Haddock on library for example-1.0..
+cabal: Failed to build documentation for example-1.0-inplace.

cabal-testsuite/PackageTests/NewHaddock/Fails/cabal.project

+packages: .
\ No newline at end of file

cabal-testsuite/PackageTests/NewHaddock/Fails/cabal.test.hs

+import Test.Cabal.Prelude
+import System.Exit (ExitCode (..))
+
+main = cabalTest $ do
+    fails $ cabal "v2-build" ["example"]
+    fails $ cabal "v2-haddock" ["example"]

cabal-testsuite/PackageTests/NewHaddock/Fails/example.cabal

+name:          example
+version:       1.0
+build-type:    Simple
+cabal-version: >=1.10
+
+library
+  default-language: Haskell2010
+  build-depends:    base
+  exposed-modules:  Example