Maintenance and merging of Valgrind and Valgrind-Freya code paths (#2362)

None of the code paths have been tested for long and especially the
Freya code paths have been long abandoned. This patch:
- Merges Valgrind-Freya into Valgrind code path (there should be no
  need to choose between them, Valgrind should work just fine).
- Removes leftover code (`VALGRIND_FREYA_CHECK_MEMPOOL_REQUEST` and
  `valgrind_freya_mempool_request`).
- Adds `JMEM_` prefix to Valgrind-related macros (to correctly
  leave the `VALGRIND_` prefix to Valgrind).
- Moves the definition of the Valgrind-related macros to a common
  header to avoid duplication.

Note: Adding a CI job to perform Valgrind Memchecks is left for
follow-up as it turns out to be excessively slow (>50 mins for a
`--jerry-tests --jerry-test-suite` run, and even a simple
`--jerry-tests` may get terminated prematurely because of timeout
issues).

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

jerry-core/jmem/jmem-allocator-internal.h

@@ -24,6 +24,27 @@
  * @{
  */
 
+ /**
+  * @{
+  * Valgrind-related options and headers
+  */
+ #ifdef JERRY_VALGRIND
+ # include "memcheck.h"
+
+ # define JMEM_VALGRIND_NOACCESS_SPACE(p, s)   VALGRIND_MAKE_MEM_NOACCESS((p), (s))
+ # define JMEM_VALGRIND_UNDEFINED_SPACE(p, s)  VALGRIND_MAKE_MEM_UNDEFINED((p), (s))
+ # define JMEM_VALGRIND_DEFINED_SPACE(p, s)    VALGRIND_MAKE_MEM_DEFINED((p), (s))
+ # define JMEM_VALGRIND_MALLOCLIKE_SPACE(p, s) VALGRIND_MALLOCLIKE_BLOCK((p), (s), 0, 0)
+ # define JMEM_VALGRIND_FREELIKE_SPACE(p)      VALGRIND_FREELIKE_BLOCK((p), 0)
+ #else /* !JERRY_VALGRIND */
+ # define JMEM_VALGRIND_NOACCESS_SPACE(p, s)
+ # define JMEM_VALGRIND_UNDEFINED_SPACE(p, s)
+ # define JMEM_VALGRIND_DEFINED_SPACE(p, s)
+ # define JMEM_VALGRIND_MALLOCLIKE_SPACE(p, s)
+ # define JMEM_VALGRIND_FREELIKE_SPACE(p)
+ #endif /* JERRY_VALGRIND */
+ /** @} */
+
 #ifdef JMEM_STATS
 void jmem_heap_stats_reset_peak (void);
 void jmem_heap_stats_print (void);