deduplicate strings sooner at load and compile

We can use rb_fstring_cstr in some places to prevent an
intermediate object from being created before deduplication
via rb_fstring.

* compile.c (iseq_compile_each): use rb_fstring_cstr
  (rb_insns_name_array): ditto
* load.c (rb_load_internal0): ditto

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57745 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

compile.c

@@ -5971,7 +5971,7 @@ iseq_compile_each(rb_iseq_t *iseq, LINK_ANCHOR *const ret, NODE *node, int poppe
       }
       case NODE_SCLASS:{
 	ID singletonclass;
-	const rb_iseq_t *singleton_class = NEW_ISEQ(node->nd_body, rb_str_new2("singleton class"),
+	const rb_iseq_t *singleton_class = NEW_ISEQ(node->nd_body, rb_fstring_cstr("singleton class"),
 						    ISEQ_TYPE_CLASS, line);
 
 	CHECK(COMPILE(ret, "sclass#recv", node->nd_recv));
@@ -6515,7 +6515,7 @@ rb_insns_name_array(void)
     VALUE ary = rb_ary_new();
     int i;
     for (i = 0; i < numberof(insn_name_info); i++) {
-	rb_ary_push(ary, rb_fstring(rb_str_new2(insn_name_info[i])));
+	rb_ary_push(ary, rb_fstring_cstr(insn_name_info[i]));
     }
     return rb_obj_freeze(ary);
 }

load.c

@@ -612,7 +612,8 @@ rb_load_internal0(rb_thread_t *th, VALUE fname, int wrap)
 	    VALUE parser = rb_parser_new();
 	    rb_parser_set_context(parser, NULL, FALSE);
 	    node = (NODE *)rb_parser_load_file(parser, fname);
-	    iseq = rb_iseq_new_top(node, rb_str_new2("<top (required)>"), fname, rb_realpath_internal(Qnil, fname, 1), NULL);
+	    iseq = rb_iseq_new_top(node, rb_fstring_cstr("<top (required)>"),
+			    fname, rb_realpath_internal(Qnil, fname, 1), NULL);
 	}
 	rb_iseq_eval(iseq);
     }