* testenv/test/base_test.py: Add --gen-suppressions=all to valgrind options
* tests/Test-proxied-https-auth.px: Likewise
* tests/WgetTests.pm: Likewise

This reverts commit 79be99aff4717a75ec7531d8b3a4ec96341754ca.

/usr/bin/env 8.28 and below doesn't know -S.

* tests/*.px: Add -I . to the shebang

This allows perl test to be run from tests/ directory, e.g. via
  ./Test--post-file.px

* tests/FTPServer.pm: Escape '{' in RE to fix warnings
* tests/FTPTest.pm: Likewise
* tests/HTTPServer.pm: Likewise
* tests/HTTPTest.pm: Likewise
* tests/Test-proxied-https-auth-keepalive.px: Likewise
* tests/Test-proxied-https-auth.px: Likewise
Escape '{' in RE to fix warnings:
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/{{ <-- HERE port}}/

    * tests/Makefile.am: Add valgrind-suppressions-ssl to EXTRA_DIST
    * tests/Test-proxied-https-auth-keepalive.px: Find valgrind in
    correct path during make distcheck
    * tests/Test-proxied-https-auth.px: Same

* tests/Test-proxied-https-auth-keepalive.px: Skip test if perl module
  IO::Socket::SSL is not installed (trivial change).
* tests/Test-proxied-https-auth.px: Skip test if perl module
  IO::Socket::SSL is not installed (trivial change).

    * testenv/test/base_test.py: Use Valgrind SSL suppressions file for
    tests
    * testenv/valgrind-suppression-ssl, tests/valgrind-suppression-ssl:
    Add new suppression files to suppress OpenSSL errors in valgrind
    * tests/test-proxied-https-auth.px: Use the valgrind SSL
    suppressions file for the test
    * tests/test-proxied-https-auth-keepalive.px: Same

   add valgrind support,
   sync parent / child (client / server)

Fixed the missing synchronization between server and client.
Without this, we experienced random test failures.
Also added valgrind support.