[openssl/openssl] 552603: Coverity 1508534 & 1508540: misuses of time_t

[Pauli]

  Branch: refs/heads/OpenSSL_1_1_1-stable
  Home:   https://github.com/openssl/openssl
  Commit: 552603edfed18f30466277d29b70939390fea65b
      https://github.com/openssl/openssl/commit/552603edfed18f30466277d29b70939390fea65b
  Author: Pauli <pauli at openssl.org>
  Date:   2022-08-19 (Fri, 19 Aug 2022)

  Changed paths:
    M ssl/statem/extensions_clnt.c
    M ssl/statem/extensions_srvr.c

  Log Message:
  -----------
  Coverity 1508534 & 1508540:  misuses of time_t

Avoid problems when the lower 32 bits of time_t roll over by delaying
the cast to integer until after the time delta has been computed.

Reviewed-by: Ben Kaduk <kaduk at mit.edu>
Reviewed-by: Matt Caswell <matt at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19004)

(cherry picked from commit a6cadcbdc3b4f3fbd0fd228e41177f0661b68264)