test(e107RequireLegacyTemplate): rewrite cache-reuse template body to PHP 5.6-safe form

testRequireReusesCacheOnSecondCall builds a PHP template source as a
string, writes it to a temp file, and require()s the file three times.
The original body used null-coalescing (??) to seed $GLOBALS['__test_cached'],
which PHP 5.6 parses at require-time and fatals on, killing the test
process with exit 255 before PHPUnit can record the failure. Every test
in the file runs to completion on PHP 5.6 except this one, and the two
that come after it never get a chance to execute.

Rewrite the body to use isset()-ternary, which is semantically identical
and parses cleanly on every PHP version in the matrix. The test itself
(the outer file) was already 5.6-safe because the ?? lived inside a
string literal; only the templated source needed updating.

Author: e107help

e107_tests/tests/unit/e107RequireLegacyTemplateTest.php

@@ -216,8 +216,10 @@ public function testRequireWithNoLanReferencesIsNoop()
 	public function testRequireReusesCacheOnSecondCall()
 	{
 		// Indirect check: second call with same path should still work (and
-		// for templates with no LAN_*, must not emit warnings).
-		$body = "<?php\n\$GLOBALS['__test_cached'] = (\$GLOBALS['__test_cached'] ?? 0) + 1;\n";
+		// for templates with no LAN_*, must not emit warnings). The body
+		// uses isset()-ternary rather than ?? because PHP 5.6 has to parse
+		// the templated source on require, and ?? is a parse error there.
+		$body = "<?php\n\$GLOBALS['__test_cached'] = (isset(\$GLOBALS['__test_cached']) ? \$GLOBALS['__test_cached'] : 0) + 1;\n";
 		$path = $this->writeTempTemplate('cached.php', $body);
 
 		e107::requireLegacyTemplate($path);