Remove gdb-testsuite-readline63-sigint-revert.patch

This patch was removed with the 10.2 rebase (commit 8594aea),
but appears to have been accidentally reintroduced with the 11.1 rebase
(commit 1f618b9).

gdb-testsuite-readline63-sigint-revert.patch

@@ -1,33 +0,0 @@
-diff --git b/gdb/testsuite/gdb.gdb/selftest.exp a/gdb/testsuite/gdb.gdb/selftest.exp
-index 7e6a4e1..969797a 100644
---- b/gdb/testsuite/gdb.gdb/selftest.exp
-+++ a/gdb/testsuite/gdb.gdb/selftest.exp
-@@ -451,25 +451,9 @@ proc test_with_self { executable } {
-     }
-     
-     set description "send SIGINT signal to child process"
--    gdb_test_multiple "signal SIGINT" "$description" {
--	-re "^signal SIGINT\r\nContinuing with signal SIGINT.\r\nQuit\r\n" {
--	    pass "$description"
--	}
--    }
--
--    set description "send ^C to child process again"
--    send_gdb "\003"
--    gdb_expect {
--	-re "(Thread .*|Program) received signal SIGINT.*$gdb_prompt $" {
--	    pass "$description"
--	}
--	-re ".*$gdb_prompt $" {
--	    fail "$description"
--	}
--	timeout {
--	    fail "$description (timeout)"
--	}
--    }
-+    gdb_test "signal SIGINT" \
-+	"Continuing with signal SIGINT.*" \
-+	"$description"
- 
-     # Switch back to the GDB thread if Guile support is linked in.
-     # "signal SIGINT" could also switch the current thread.