feat(jdbc/mysql-j-8): Add native image support for jdbc/mysql-j-8

[mpeddada1]

Part of #824

[mpeddada1]

Enabling mysql-j-8 results in the following error:

Failures (1):
  JUnit Vintage:JdbcMysqlJ8IntegrationTests:pooledConnectionTest
    MethodSource [className = 'com.google.cloud.sql.mysql.JdbcMysqlJ8IntegrationTests', methodName = 'pooledConnectionTest', methodParameterTypes = '']
    => org.opentest4j.MultipleFailuresError: Multiple Failures (2 failures)
	com.zaxxer.hikari.pool.HikariPool$PoolInitializationException: Failed to initialize pool: Could not create connection to database server.
	java.lang.NullPointerException: <no message>
       org.junit.vintage.engine.execution.TestRun.getStoredResultOrSuccessful(TestRun.java:200)
       org.junit.vintage.engine.execution.RunListenerAdapter.fireExecutionFinished(RunListenerAdapter.java:248)
       org.junit.vintage.engine.execution.RunListenerAdapter.testFinished(RunListenerAdapter.java:214)
       org.junit.vintage.engine.execution.RunListenerAdapter.testFinished(RunListenerAdapter.java:88)
       org.junit.runner.notification.SynchronizedRunListener.testFinished(SynchronizedRunListener.java:87)
       [...]
       Suppressed: com.zaxxer.hikari.pool.HikariPool$PoolInitializationException: Failed to initialize pool: Could not create connection to database server.
         com.zaxxer.hikari.pool.HikariPool.throwPoolInitializationException(HikariPool.java:596)
         com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:582)
         com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115)
         com.zaxxer.hikari.HikariDataSource.<init>(HikariDataSource.java:81)
         com.google.cloud.sql.mysql.JdbcMysqlJ8IntegrationTests.setUpPool(JdbcMysqlJ8IntegrationTests.java:85)
         [...]
       Caused by: java.sql.SQLNonTransientConnectionException: Could not create connection to database server.
         com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:110)
         com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
         com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89)
         com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63)
         com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:1000)
         [...]
       Caused by: java.lang.NullPointerException: inStream parameter is null
         java.util.Objects.requireNonNull(Objects.java:246)
         java.util.Properties.load(Properties.java:406)
         com.mysql.cj.util.TimeUtil.loadTimeZoneMappings(TimeUtil.java:226)
         com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:123)
         com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2139)
         [...]
       Suppressed: java.lang.NullPointerException
         com.google.cloud.sql.mysql.JdbcMysqlJ8IntegrationTests.dropTableIfPresent(JdbcMysqlJ8IntegrationTests.java:103)
         java.lang.reflect.Method.invoke(Method.java:566)
         org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
         org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
         org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
         [...]

Test run finished after 3201 ms
[         3 containers found      ]
[         0 containers skipped    ]
[         3 containers started    ]
[         0 containers aborted    ]
[         3 containers successful ]
[         0 containers failed     ]
[         1 tests found           ]
[         0 tests skipped         ]
[         1 tests started         ]
[         0 tests aborted         ]
[         0 tests successful      ]
[         1 tests failed          ]