This re-enables a graceful shutdown that was broken after ff78924

Closes #5693

(cherry picked from commit 9a399e2)

# Conflicts:
#	src/main/java/io/vertx/core/http/impl/Http2ConnectionBase.java

It is called from the AsyncTestBase's @before.
No explicit teardown necessary, as Vert.x instances are closed
automatically via AsyncTestBase's @after.

Closes #5851

(cherry picked from commit a07b88f)

Closes #5853

(cherry picked from commit 8c3bc97)

…eSharedServers

Only a server that has completed the listening is ready to
update the traffic shaping.

Closes #5863

Closes #5857

(cherry picked from commit 57b9c68)

… message in absence of a log message.

Motivation:

Some logging event might arrive with a null message and trigger the logging of the NULL string which is very confusing for human analyzing the a log tail.

We should improve this and provide a better message.

Changes:

Use the <missing-log-message> when no log message is provided instead of NULL.

Motivation:

HttpUtils#removeDots does not properly handle the C. rule of section 5.2.4 of RFC3986. When the output buffer
does not contain a / it should discard the entire content of the buffer.

Changes:

When handling rule C in HttpUtils#removeDots, discard the output buffer when no / is present.