lread.c: Use bare symbol operations

lread.c: Use bare symbol operations

* src/lread.c (read0, intern_sym, intern_driver, intern_1)
(intern_c_string_1, Fintern, Fintern_soft, Funintern, oblookup)
(map_obarray, init_obarray_once, defvar_int, defvar_bool)
(defvar_lisp_nopro, defvar_kboard, syms_of_lread):
Use the faster bare-symbol operations where provably correct to do so.