sage: reenable pexpect interrupt test

pkgs/applications/science/math/sage/patches/disable-pexpect-intermittent-failure.patch

@@ -1,29 +0,0 @@
-diff --git a/src/sage/interfaces/singular.py b/src/sage/interfaces/singular.py
-index 88a33b0349..b3321f0bec 100644
---- a/src/sage/interfaces/singular.py
-+++ b/src/sage/interfaces/singular.py
-@@ -495,24 +495,6 @@ class Singular(ExtraTabCompletion, Expect):
-         """
-         Send an interrupt to Singular. If needed, additional
-         semi-colons are sent until we get back at the prompt.
--
--        TESTS:
--
--        The following works without restarting Singular::
--
--            sage: a = singular(1)
--            sage: _ = singular._expect.sendline('1+')  # unfinished input
--            sage: try:
--            ....:     alarm(0.5)
--            ....:     singular._expect_expr('>')  # interrupt this
--            ....: except KeyboardInterrupt:
--            ....:     pass
--            Control-C pressed.  Interrupting Singular. Please wait a few seconds...
--
--        We can still access a::
--
--            sage: 2*a
--            2
-         """
-         # Work around for Singular bug
-         # http://www.singular.uni-kl.de:8002/trac/ticket/727

pkgs/applications/science/math/sage/sage-src.nix

@@ -87,9 +87,6 @@ stdenv.mkDerivation rec {
       rev = "2959ac792ebd6107fe87c9af1541083de5ba02d6";
       sha256 = "sha256-bWIpEGir9Kawak5CJegBMNcHm/CqhWmdru+emeSsvO0=";
     })
-
-    # disable pexpect interrupt test (see https://trac.sagemath.org/ticket/30945)
-    ./patches/disable-pexpect-intermittent-failure.patch
   ];
 
   # Patches needed because of package updates. We could just pin the versions of