Track define()'d constants as exported nodes

[SanderMuller]

Follow-up to #6023.

Global constants declared with define() have the same result-cache staleness that #6023 fixed for const. A file reading a define()'d constant records a dependency on the defining file (via the ConstFetch handling from #6023), but a define() is a function call rather than a declaration, so it produced no exported node. The result cache re-analyses a changed file's dependents only when its exported nodes change, so changing the define()'s value did not re-analyse the reading files.

This exports define('NAME', <value>) calls that have a literal name, reusing the ExportedConstantNode from #6023, so changing the value re-analyses the dependents.

Reproducing the staleness

// define.php
define('SOME_DEFINED_MODE', 1);

// consumer.php
namespace App;
function usesDefinedMode(): int { return SOME_DEFINED_MODE; }

vendor/bin/phpstan analyse define.php consumer.php   # no errors; cache warm
# change define.php to: define('SOME_DEFINED_MODE', 'str');
vendor/bin/phpstan analyse define.php consumer.php   # before: stale, still no error

Before this change the second run keeps consumer.php cached and reports nothing; with it, the consumer is re-analysed and reports the return-type error, matching a cold run. Covered by the result-cache-define e2e test.

[phpstan-bot]

This pull request has been marked as ready for review.

[staabm]

thank you!