Default value changed following discussion on valdev.
Giving more information for errors with freed blocks can help
when investigating difficult problems (e.g. double free, programs
using 'cleanup list' collecting different types of memory, ...)
Regression tested on various setup (x86, ppc64, s390x, amd64, debian or fedora)
Tests that have only one exp files have been updated to use the output
of the new default value in their .exp file.
Tests having more than one exp file have been changed so as to
specify explicitely the previous clo default value (i.e. adding
--keep-stacktraces=alloc-then-free in the vgtest file).
Possibly, some tests might fail on non tested platforms
(e.g. mips, macos, solaris, tilegx).
Fixes should be straightforward, using one of the above fix techniques.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@15597
