v1.0.x → master upmerge.

change back slashes to forward slashes in grpc.tool nuspec

Change C++ API to expose wait_for_ready instead of fail_fast.

PHP: require grpc extension to be installed before composer package

Fix grpclb LB policy pick method to return 0 upon error.

clang-format fix

Critical: backport #8316

Fix C++ filter API header.

Critical: dont eat run_tests.py errors on test failure

Drop unnecessary return statement.

Add missing delete

Fix maybe-uninitialized variable

Fix cronet compilation error

Fix grpc_byte_buffer_copy to copy compression algorithm

Add QUIC support to Objective C

Resolve memory leak in cronet_transport

Improve ProtoReflectionDescriptorDatabase

Remove GRPC_NEED_UDP ifdefs

Add script to reboot a jenkins slave

Fix handling of max receive message size on client side.

Backport matrix runner scripts into v1.0.x

Backport: fix building go interop image