pcre preserves byte strings
pcre preserves byte strings

fixes https://github.com/peachpiecompiler/peachpie/issues/178
- in case a binary string can be preserved, it is
- reuses original value if possible to save some mem

peachpiecompiler/peachpie,iolevel/peachpie-concept,peachpiecompiler/peachpie,iolevel/peachpie,iolevel/peachpie-concept,iolevel/peachpie,iolevel/peachpie,iolevel/peachpie-concept,peachpiecompiler/peachpie