This patch adds two new string concatenation functions:
ecma_append_chars_to_string and ecma_append_magic_string_to_string
The former appends a cesu8 byte array and the latter appends a magic string
to the end of an ecma-string. These two free (dereference) their ecma-string
argument, and this change is also applied to the original ecma_concat_ecma_strings
function which simplifies string handling in most cases.
JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com