Update the RegExp constructor to ECMA-262 v6 (#3538)

The following methods have been implemented:
- RegExpAlloc, based on ECMA-262 v6, 21.2.3.2.1
- RegExpInitialize, based on ECMA-262 v6, 22.2.3.2.2
- RegExpCreate, based on ECMA-262 v6, 21.2.3.2.3

Co-authored-by: Robert Fancsik frobert@inf.u-szeged.hu
JerryScript-DCO-1.0-Signed-off-by: Adam Szilagyi aszilagy@inf.u-szeged.hu

jerry-core/ecma/base/ecma-globals.h

@@ -940,6 +940,13 @@ typedef struct
                                      *   If regexp, the other flags must be RE_FLAG... */
 } ecma_compiled_code_t;
 
+/**
+ * The proper memory size for the RegExp.prototype. We have to align the header's size manually, because
+ * in the struct, it is aligned to 8 bytes during the compilation.
+ */
+#define ECMA_REGEXP_PROTO_COMPILED_CODE_SIZE \
+  (JERRY_ALIGNUP (sizeof (ecma_compiled_code_t), JMEM_ALIGNMENT) + sizeof (ecma_value_t))
+
 #if ENABLED (JERRY_SNAPSHOT_EXEC)
 
 /**