test: correct isReused parameter in test-http-parser

While backporting #23272 to v10.x and v8.x I noticed that the isReused parameters used in the two reinitialize calls in this test should actually be true instead of false to better reflect the actual usage here (the parser is being reused).

This does not have any effect on the test result here (since we do not test async_hooks calls here) but for the sake of consistency the test should use the API correctly.

Refs: #23272

Checklist

• make -j4 test passes
• commit message follows commit guidelines