Add assertions for header count in HTTP request tests

This commit adds assertions to check the number of headers in HTTP request objects. This ensures that the header count is verified for better test accuracy and completeness.

test/assert_tiny_http_server_lib.c

@@ -51,6 +51,7 @@ void test_request_post_root_curl(void) {
     assert(http_req->method == POST);
     assert(http_req->version == HTTP_1_0);
     assert(strncmp(http_req->url, "/one/two/three", 255) == 0);
+    assert(http_req->headers_cnt == 6);
     assert(strncmp(http_req->headers[0]->name, "Content-Type", 255) == 0);
     assert(strncmp(http_req->headers[0]->value, "application/json", 255) == 0);
     assert(strncmp(http_req->headers[1]->name, "User-Agent", 255) == 0);
@@ -87,6 +88,7 @@ void test_request_post_root_curl_with_wide_chars(void) {
     assert(http_req->method == POST);
     assert(http_req->version == HTTP_1_0);
     assert(strncmp(http_req->url, "/one/🐌/three", 255) == 0);
+    assert(http_req->headers_cnt == 7);
     assert(strncmp(http_req->headers[0]->name, "Content-Type", 255) == 0);
     assert(strncmp(http_req->headers[0]->value, "application/json", 255) == 0);
     assert(strncmp(http_req->headers[1]->name, "User-Agent", 255) == 0);