Add mem_stats.sh tool
Add mem_stats.sh tool

Adapted from jerry's mem_stats.sh. The following changes have been
made:
* IoT.js does not ask for "separate" mem stats from jerry and so
  statistics are only printed at the end of execution. Thus, there
  is only one "Peak Heap" column.
* IoT.js has a slightly different command line syntax to trigger
  mem stats (--memstat after the js file, not --mem-stats before
  it).
* Some IoT.js "pass tests" (which are used for memory benchmarking
  for the time being) require to be executed from their containing
  directory. Thus, the readlink command line utility is used to
  retrieve the canonical path of some files and then some directory
  changes happen.
* Because of the strict 80 characters-per-line limit, some lines
  are broken.
* Added better usage info than that found in jerry's mem_stats.sh.

Note: Max RSS computation is done via the rss-measure.sh script of
jerry, which is not copied/adapted but used from within
deps/jerry/tools.)

IoT.js-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

lemmaa/iotjs,lemmaa/iotjs,lemmaa/iotjs