We recently started running grpc interceptors on local RPCs (in cockroachdb#76306).
There's a bug in there causing server-side streaming interceptors to not
work as intended. A server-side streaming interceptor is supposed to
wrap a streaming RPC handler and it has the option of overriding the
ServerStream provided to the handler with a custom one. An RPC handler
uses the ServerStream to communicate with the caller; custom
implementations of ServerStream generally wrap the gRPC implementation,
adding more transparent functionality (for example, they can override
the Context that the handler runs in).

The bug was causing the custom ServerStream provided by the interceptors
to not actually be passed to the RPC handler for local RPCs (i.e. for
streaming RPCs going through the internalClientAdapter - and there's
only one such RPC: RangeFeed). Instead, the handler always was getting
the vanilla gRPC ServerStream.
The bug was in the following lines in internalClientAdapter.RangeFeed():

  rfAdapter := rangeFeedServerAdapter{rangeFeedPipe: streamPipe}
  handler := func(srv interface{}, stream grpc.ServerStream) error {
          return a.server.RangeFeed(args, rfAdapter)
  }

We're passing `rfAdapter` to a.server.RangeFeed(), when we should be
passing `stream`. Making that change needs a bit of massaging, though.

I've also cleaned up the code surrounding the streaming interceptors and
tried to explain it better, as it was hard to follow. I've also added a
test. The code still remains pretty convoluted, but I believe that
that's inherently necessary given the gRPC interfaces we're working
with.

The bug was manifesting itself as span use-after-finish crashes in
tests for the RangeFeed RPC. Because the RangeFeed handler was not using
the ServerStream provided by the tracing server-side streaming
interceptor, the handler was running in the client's Context, with the
client-side tracing span. The client's (DistSender's) span is sometimes
finished while the server-side RPC is still running, resulting in the
use-after-finish.

Fixes cockroachdb#82571
Fixes cockroachdb#82577
Fixes cockroachdb#82578
Fixes cockroachdb#82579
Fixes cockroachdb#82580
Fixes cockroachdb#82581
Fixes cockroachdb#82583
Fixes cockroachdb#82585
Fixes cockroachdb#82603

Release note: None