THRIFT-5951: Add PHP runtime coverage tests

[sveneld]

Summary

• add 12 PHP runtime coverage tests for previously uncovered classes in lib/php/lib
• cover TBase, TProtocol skip paths, TMultiplexedProcessor, StoredMessageProtocol, base server/transport abstractions, JSON/SimpleJSON helper contexts, TApplicationException, and constant/type classes
• keep production PHP runtime code unchanged

Notes

• JIRA: THRIFT-5951
• this PR adds tests only
• no third-party dependencies were added
• LICENSE and NOTICE are unchanged

Validation

• docker run --rm -v "$PWD:/src" -w /src php:8.3-cli php vendor/bin/phpunit -c lib/php/phpunit.xml --filter '/(TBaseTest|TProtocolTest|TMultiplexedProcessorTest|StoredMessageProtocolTest|TServerTest|TServerTransportTest|TTransportTest|JsonContextTest|SimpleJsonContextTest|TApplicationExceptionTest|ExceptionTypesTest|TypeConstantsTest)/' lib/php/test/Unit/Lib
• docker run --rm -v "$PWD:/src" -w /src php:8.3-cli sh -lc 'for f in lib/php/test/Unit/Lib/Base/TBaseTest.php lib/php/test/Unit/Lib/Protocol/TProtocolTest.php lib/php/test/Unit/Lib/TMultiplexedProcessorTest.php lib/php/test/Unit/Lib/StoredMessageProtocolTest.php lib/php/test/Unit/Lib/Server/TServerTest.php lib/php/test/Unit/Lib/Server/TServerTransportTest.php lib/php/test/Unit/Lib/Transport/TTransportTest.php lib/php/test/Unit/Lib/Protocol/JsonContextTest.php lib/php/test/Unit/Lib/Protocol/SimpleJsonContextTest.php lib/php/test/Unit/Lib/Exception/TApplicationExceptionTest.php lib/php/test/Unit/Lib/Exception/ExceptionTypesTest.php lib/php/test/Unit/Lib/Type/TypeConstantsTest.php; do php -l "$f" || exit 1; done'

Generated-by: Codex GPT-5.4

[kpumuk]

There is something weird going on here with mocks. readAll returns strings, but skipBinary() does math on it:

return 4 + $itrans->readAll($len);

In this case since we return '12' as a string, 4 + '12' will be 16. Curious how does it even work...

[kpumuk]

What happens if you return 'aa' instead of '12'?

Edit:

There was 1 error:

1) Test\Thrift\Unit\Lib\Protocol\TProtocolTest::testSkipBinarySkipsPrimitiveAndContainerValues
TypeError: Unsupported operand types: int + string

/thrift/src/lib/php/lib/Protocol/TProtocol.php:289
/thrift/src/lib/php/test/Unit/Lib/Protocol/TProtocolTest.php:190

ERRORS!
Tests: 222, Assertions: 462, Errors: 1, Skipped: 5.

I think we have a bug in the protocol implementation, and that the test does not actually test the right thing due to mocks and inputs creatively crafted around the bug.