merge revision(s) 59318572,76e2370f: [Backport #16041]

	Fix dangling path name from fstring

	* parse.y (yycompile): make sure in advance that the `__FILE__`
	  object shares a fstring, to get rid of dangling path name.
	  Fixed up 53e9908d.  [Bug #16041]

	* vm_eval.c (eval_make_iseq): ditto.

	Fix dangling path name from fstring

	* load.c (rb_require_internal): make sure in advance that the path
	  to be loaded shares a fstring, to get rid of dangling path name.
	  Fixed up 59318572.  [Bug #16041]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_6@67736 b2dd03c8-39d4-4d8f-98ff-823fe69b080e