[DOR-895] Change test value so that it doesn't match the default

As spotted in !1266, there'd be no difference in behaviour between this
test doing the right or wrong thing since they'd both return the same
value.

tests/BamReaderTest.cpp

@@ -84,15 +84,17 @@ TEST_CASE("HtsReaderTest: get_tag", TEST_GROUP) {
 
     dorado::HtsReader reader(sam.string(), std::nullopt);
     while (reader.read()) {
-        // All records in small.sam have this set to 0.
-        CHECK(reader.get_tag<int>("rl") == 0);
+        // All records in small.sam have these set.
+        CHECK(reader.get_tag<int>("XA") == 42);
+        CHECK(reader.get_tag<std::string>("XB") == "test");
         // Intentionally bad tag to test that missing tags don't return garbage.
         CHECK(reader.get_tag<int>("##") == 0);
         CHECK(reader.get_tag<float>("##") == 0);
         CHECK(reader.get_tag<std::string>("##") == "");
         // Type mismatch doesn't crash.
-        CHECK(reader.get_tag<float>("rl") == 0);
-        CHECK(reader.get_tag<std::string>("rl") == "");
+        CHECK(reader.get_tag<int>("XB") == 0);
+        CHECK(reader.get_tag<float>("XB") == 0);
+        CHECK(reader.get_tag<std::string>("XA") == "");
     }
 }