Adds regression test for dumptests.

This only checks that a function with signature [32] -> [32] -> [32] will
succeed with the :dumptests command. More tests could/should be added.

Since this test creates a file called add32.out, I added tests/regression/*.out
to the .gitignore. I'm not sure if this is the right approach or if we should
make an attempt to clean up this subdirectory after the tests finish.

.gitignore

@@ -30,3 +30,4 @@ cryptol-2.*
 # ignore test suite output
 /bin
 /output
+/tests/regression/*.out

tests/regression/dumptests.cry

@@ -0,0 +1,2 @@
+add32 : [32] -> [32] -> [32]
+add32 x y = x + y

tests/regression/dumptests.icry

@@ -0,0 +1,3 @@
+:set tests=100
+:l dumptests.cry
+:dumptests add32.out add32

tests/regression/dumptests.icry.stdout

@@ -0,0 +1,3 @@
+Loading module Cryptol
+Loading module Cryptol
+Loading module Main