Added new api to b64.h for directly encoding to memory.
Using slice_sub instead of string operations for separating
path from query.

When using GET verb, the request payload is now communicated as a base64
encoded string in the query parameter. Deleted the code that wrote/read
a custom header field (payload-bin), since caches don't consider this
field when looking for a cache hit.

Embed mock SSL data into ssl_server_fuzzer.c and add fuzzer options

Include x.pb.h instead of x.grpc.pb.h for message-only protos

Remove grpc_udp_server dependency on grpc_server.

Correct Kokoro scripts

add missing header

Trim deadline setting out of call creation path

Add import prefix to Python code generator.

Fix Copy and Unref Bug

- this is both the point where we *know* we have a config (or not), and the
  last moment before wait_until_ready-ness is not an issue

Make testing scripts python3.x compatible.

This is needed by a customer with a nontraditional codebase.

Add some pollset benchmarks

Fix flush read

Upmerge v1.2.x

Use the right encoding overhead number in remote interop test with Cronet

Don't track allocations if we are not going to use the tracking results

Track memory as part of microbenchmark profiling runs

Skip split_definitions_test if PyPy is used as an interpreter.

PHP benchmarking performance client, proxied through Ruby

Temporarily disable resource quota QPS tests

run_tests_matrix: ignore the number of failed skipped tests

Fix sanity