Grpc Tools: update JDK; fix the interop server transport flag

Muting an extremely chatty log line.

- necessary to allow seamless interop testing, as discussed earlier this week.

Send a scheme of http or https as appropriate, rather than grpc.

1. scheme_from_args should return const char*
2. Rename grpc.scheme arg to grpc.http2_scheme, and define a macro for
it.

Remove unused private field

Remove go codegen from this repository

Build all targets for a config at once

Fix return behavior of run_tools.py

Make the C++ API use C API calls to fiddle with status

This prevents mismatches from breaking tests.

So that later cancellations do not clobber status.

If not running in forever mode, and a test fails, fail run_tests.py
also.

If running in forever mode and make fails, wait for the next run.

Make cpp codegen consistent with protoc in template format.

Properly mask signals in unit tests

Compile fix for mac

Node client constructor

Various win32 fixes.

Removing a few more traces of libevent.

Now all the gpr tests build and run under win32.

This requires additional logic to determine whether to send http or
https. This change assumes a default of http, and plumbs down https
through a synthesized channel arg when using the ssl transport.