Make time independent tracing output by default in one file per process
Structure is filename.txt : list of all the files to open
folder filename.txt_files : all files, with unique names (so that they won't be erased by a new run, only the main one will)

Adds an option tracing/smpi/format/ti_one_file to only use one subfile and put every event in it
For larger runs this will avoid opening too many handles.
(cherry picked from commit dc0e44715d73224df3cff50a9a0f42e73b1afc8c)
Trace buffer is not to be handled by the format-dependent init functions
(cherry picked from commit 8ec4cdb61b9430ccbbb5f07e48d46039aa72609f)
change tesh test to account for new structure in time independent traces
Not ideal, as tesh is a bit too strict to allow us to really compare the files
(cherry picked from commit bf31c01ca3d4167bd748658b02b5938231f23fc5)
Request should not be null here.
(cherry picked from commit b8fc5d84a6fcf56a745815d784bc10ebbeb6e68a)
Avoid to dereference a null index when HAVE_TRACING.
(cherry picked from commit df9b8b6931c264f2e2877e201e31019e6e7dcad3)
Simplify logic, and free loc in all cases.
(cherry picked from commit 903f71895fc1cfd7bbc7609c57b9d09153b7011e)
Misc cleanups.

* stat'ing the directory before mkdir is just wrong (race condition),
  remove this test and let fopen report any error;
* use mode 0777 for mkdir, and let the user adjust his umask;
* use xbt_free() instead of free();
* remove useless tests before xbt_{dict,dynar}_free();
* and the usual reindent.
(cherry picked from commit 332285d51119f8f98270655bf88f485a9f914df1)