Don't load drivers through the service loader

This was introduced in quarkusio#7089,
which was specifically about a bug when using opentracing,
which no longer has an extension in core,
and even its Quarkiverse extension is no longer maintained:
https://github.com/quarkiverse/quarkus-smallrye-opentracing

The service loading is also causing problems with quarkusio#41995

So, let's not do it all, assuming tests passes.

extensions/agroal/runtime/src/main/java/io/quarkus/agroal/runtime/DataSources.java

@@ -1,12 +1,9 @@
 package io.quarkus.agroal.runtime;
 
 import java.sql.Connection;
-import java.sql.Driver;
 import java.sql.Statement;
 import java.util.Collection;
-import java.util.Iterator;
 import java.util.Map;
-import java.util.ServiceLoader;
 import java.util.Set;
 import java.util.stream.Collectors;
 
@@ -157,9 +154,6 @@ public AgroalDataSource createDataSource(String dataSourceName) {
                     "Datasource " + dataSourceName + " does not have a JDBC URL and should not be created");
         }
 
-        // we first make sure that all available JDBC drivers are loaded in the current TCCL
-        loadDriversInTCCL();
-
         AgroalDataSourceSupport.Entry matchingSupportEntry = agroalDataSourceSupport.entries.get(dataSourceName);
         String resolvedDriverClass = matchingSupportEntry.resolvedDriverClass;
         Class<?> driver;
@@ -354,21 +348,4 @@ public boolean isValid(Connection connection) {
         poolConfiguration.flushOnClose(dataSourceJdbcRuntimeConfig.flushOnClose());
     }
 
-    /**
-     * Uses the {@link ServiceLoader#load(Class) ServiceLoader to load the JDBC drivers} in context
-     * of the current {@link Thread#getContextClassLoader() TCCL}
-     */
-    private static void loadDriversInTCCL() {
-        // load JDBC drivers in the current TCCL
-        final ServiceLoader<Driver> drivers = ServiceLoader.load(Driver.class);
-        final Iterator<Driver> iterator = drivers.iterator();
-        while (iterator.hasNext()) {
-            try {
-                // load the driver
-                iterator.next();
-            } catch (Throwable t) {
-                // ignore
-            }
-        }
-    }
 }