bug#36567: cl-defgeneric defeats (with-suppressed-warnings ((obsolete fun)) ...)

[Stefan Kangas <stefan@marxist.se>]

cl-defgeneric defeats with-suppressed-warnings on current
master under certain circumstances.

Steps to reproduce:
0. emacs -Q
1. C-x C-f foo.el RET
2. Insert into buffer:

(require 'cl-generic)
(cl-defgeneric foo ()
  (declare (obsolete nil nil))
  t)

3. C-x C-e    [i.e. evaluate foo]
4. Insert into buffer:

(with-suppressed-warnings ((obsolete foo))
  (foo))

5. C-x C-s
6. M-x byte-compile-file RET foo.el RET

Result:
*Compile-Log* buffer contains:
foo.el:3:22:Warning: ‘foo’ is an obsolete generic function.

Expected result:
*Compile-Log* buffer contains no warning.


In GNU Emacs 27.0.50 (build 2, x86_64-apple-darwin15.6.0, NS
appkit-1404.47 Version 10.11.6 (Build 15G22010))
 of 2019-07-10 built on Stefans-MBP
Repository revision: 77cf71ce8cc611ecfd143277441e2ad4acc9401b
Repository branch: master
Windowing system distributor 'Apple', version 10.3.1404
System Description:  Mac OS X 10.11.6