vm_method.c: no RTEST on mere flag

* vm_method.c (basic_obj_respond_to): `priv` is not a VALUE but a
  mere flag, so cannot call RTEST() on it.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46442 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
string.c: no copy of interned strings

* string.c (sym_succ, sym_cmp, sym_casecmp, sym_match, sym_aref):
  not need to make copy of interned strings, use directly.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46443 b2dd03c8-39d4-4d8f-98ff-823fe69b080e