Previous the api used spv_text_t and spv_binary_t for both input
and output, but depending on the usage, you either MUST
call spvBinaryDestroy or you MUST NOT call spvBinaryDestroy on the
pointer.
Always try to destroy the binary during common methods
of test fixtures. This is safe if no other code in the test
attempted to destroy the binary.
Take advantage of the fact spvBinaryDestroy is a no-op on a nullptr,
by eliminating the null pointer check in the caller.
Fix the bug that TextAdvance() forgot to skip whitespace at the
beginning of the next line after a comment line.
Fix the bug that TextAdvanceLine() increase line number after going
over a character.
