Part of https://github.com/harfbuzz/harfbuzz/issues/1652

Add a check for stringOffSet(uint16) overflow,
return early if overflow happens

Notably, add hb_is_source_of(,) and hb_is_sink_of(,) to replace most
uses of hb_is_iterator_of(,).

NameRecord is not copy-constructible, so should be iterator of
const-reference.

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=14641

This reverts commit c7f366fb.

Don't know how it got to master!

selection of which name records to keep in the subset method.

elements and serialize method

string

Part of https://github.com/harfbuzz/harfbuzz/issues/1652

Part of https://github.com/harfbuzz/harfbuzz/issues/1553

In file included from hb-ot-name.cc:29:
hb-ot-name-table.hh: In member function 'unsigned int OT::name::get_size() const':
hb-ot-name-table.hh:157: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
hb-open-type.hh:354: note: candidate 1: const Type& OT::UnsizedArrayOf<Type>::operator[](unsigned int) const [with Type = OT::NameRecord]
hb-ot-name-table.hh:157: note: candidate 2: operator[](const T*, int) <built-in>
hb-ot-name-table.hh: In member function 'void OT::name::accelerator_t::init(hb_face_t*)':
hb-ot-name-table.hh:196: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
hb-dsalgs.hh:574: note: candidate 1: Type& hb_array_t<Type>::operator[](unsigned int) const [with Type = const OT::NameRecord]
hb-ot-name-table.hh:196: note: candidate 2: operator[](T*, int) <built-in>
hb-ot-name-table.hh:197: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
hb-dsalgs.hh:574: note: candidate 1: Type& hb_array_t<Type>::operator[](unsigned int) const [with Type = const OT::NameRecord]
hb-ot-name-table.hh:197: note: candidate 2: operator[](T*, int) <built-in>
hb-ot-name-table.hh:198: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
hb-dsalgs.hh:574: note: candidate 1: Type& hb_array_t<Type>::operator[](unsigned int) const [with Type = const OT::NameRecord]
hb-ot-name-table.hh:198: note: candidate 2: operator[](T*, int) <built-in>
make[4]: *** [libharfbuzz_la-hb-ot-name.lo] Error 1
make[3]: *** [all-recursive] Error 1