Streaming tests for HTTPx

Problem

HTTPx needs streaming tests too.

Solution

Port streaming tests for HTTPx from HTTP tests
introduced in RB_ID=516495.

Result

HTTPx also tested for streaming failure cases.

RB_ID=526003
Finagle, Ostrich, Util: Fix sbt project definition

Problem

Finagle was not compiling with sbt for multiple reasons:
- the java compilation of AbstractCloseAwaitably.java required one extra import
- finagle-httpx-compat required direct dependencies on finagle-http(x)

Solution

Fix the sbt project definition of Util/Finagle.
While I was there, I cleaned up some scaladoc warning in util and
some compilation warning in ostrich.

RB_ID=525909
remove newlines from test names so junit can generate correct XML files

CI relies on JUNIT XML files for certain things, such as retrying failed
tests. When test names have "newlines" in them, junit can't generate
correct XML files. This change fixes that.

RB_ID=526901
finagle-kestrel: Add Java compilation tests and Java API for ReadHandle

RB_ID=521667
finagle-core: Add log in case of instantiation failure in LoadService

Problem

The instantiation of a new class in LoadService can throw an exception
(IncompatibleClassChangeError, ...). The cause of this exception is
(most of the time) diamond dependencies or bad classpath.
That's easy to fix as soon as you know which class caused the exception.

Solution

Add a FATAL log when one of the instantiation fails, and continue the
loading without the failing instance. This should drastically simplify
the debugging.

RB_ID=525813
[finagle-httpx-compat]: Netty client adaptor

Problem

We have the adaptors for services, but not for clients. To provide
complete coverage we need an adaptor to convert an HTTPx client into
a Netty client (related: RB_ID=497155).

Solution

A filter to wrap an HTTPx client so that it can be used with
Netty types.

Result

Ability to use HTTPx clients with Netty types.

RB_ID=527557
TBR=true