Follow-up refactoring of logging-related parts

This patch:
* Ensures that all calls to `jerry_port_log` in jerry-core happen
  via macros defined in jrt.h. Also, it unifies the names of those
  macros: as `JERRY_ERROR_MSG` and `JERRY_WARNING_MSG` gave a good
  pattern that was well aligned with the naming scheme of the log
  level enum, `JERRY_DLOG` and `JERRY_DDLOG` were rewritten to
  `JERRY_DEBUG_MSG` and `JERRY_TRACE_MSG`.
* Ensures that all debug logging code parts of jerry-core (i.e.,
  memory statistics, JS byte-code dumps, and RegExp byte-code
  dumps) are guarded by macros: `JMEM_STATS`,
  `PARSER_DUMP_BYTE_CODE`, and `REGEXP_DUMP_BYTE_CODE`, which in
  turn are controled by cmake build system feature flags
  `FEATURE_MEM_STATS`, `FEATURE_PARSER_DUMP`, and
  `FEATURE_REGEXP_DUMP`.
* Ensures that all debug logging functionalities can be controled
  during run time (provided that they were enabled during build
  time): the engine has `JERRY_INIT_MEM_STATS[_SEPARATE]`,
  `JERRY_INIT_SHOW_OPCODES`, `JERRY_INIT_SHOW_REGEXP_OPCODES` init
  flags, and the default unix/linux command line app has
  corresponding command line switches.`
* Drops `FEATURE_LOG`, `JERRY_ENABLE_LOG`, and
  `JERRY_INIT_ENABLE_LOG`, as their name was misleadingly general,
  even though they mostly controled the regexp engine only. The
  above-mentioned `*REGEXP*` things mostly act as their
  replacements.
* Updates build, test, and measurement tool scripts, and
  documentation.

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

tools/run-mem-stats-test.sh

@@ -43,7 +43,7 @@ function is_mem_stats_build
   [ -x "$1" ] || fail_msg "Engine '$1' is not executable"
 
   tmpfile=`mktemp`
-  "$1" --mem-stats $tmpfile 2>&1 | grep -- "Ignoring memory statistics option because of '!JMEM_STATS' build configuration." 2>&1 > /dev/null
+  "$1" --mem-stats $tmpfile 2>&1 | grep -- "Ignoring JERRY_INIT_MEM_STATS flag because of !JMEM_STATS configuration." 2>&1 > /dev/null
   code=$?
   rm $tmpfile