Fix PHPT ENV sections

run-tests.php assumes the contents of an ENV section are a simple list
of key-value-pairs, instead of evaluating the section contents as PHP
script which server-tests.php did.  Since server-tests.php is gone, we
remove the superfluous and confusing scripting.

ext/filter/tests/bug49184.phpt

@@ -5,9 +5,7 @@ See Bug #49184
 --SKIPIF--
 <?php if (!extension_loaded("filter")) die("skip needs filter ext"); ?>
 --ENV--
-return <<<END
 HTTP_X_FORWARDED_FOR=example.com
-END;
 --FILE--
 <?php
   var_dump(filter_input(INPUT_SERVER, "HTTP_X_FORWARDED_FOR", FILTER_UNSAFE_RAW));

ext/snmp/tests/snmp2_set-nomib.phpt

@@ -7,9 +7,7 @@ Boris Lytockin
 require_once(dirname(__FILE__).'/skipif.inc');
 ?>
 --ENV--
-return <<<END
 MIBS=
-END;
 --FILE--
 <?php
 require_once(dirname(__FILE__).'/snmp_include.inc');

ext/snmp/tests/snmpset-nomib.phpt

@@ -7,9 +7,7 @@ Boris Lytochkin
 require_once(dirname(__FILE__).'/skipif.inc');
 ?>
 --ENV--
-return <<<END
 MIBS=
-END;
 --FILE--
 <?php
 require_once(dirname(__FILE__).'/snmp_include.inc');