fix 339156 - gdbsrv not called for fatal signal

In preparation for removing --db-attach=yes, call gdbserver
for a fatal signal (where --db-attach=yes is also calling gdb)



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14556 a5019735-40e9-0310-863c-91ae7b9d1cf9
Remove anouncement of helgrind dead in coregrind/m_debuginfo/README.txt
as helgrind died many years ago, but resuscitate since then.



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14557 a5019735-40e9-0310-863c-91ae7b9d1cf9