clang-format all core files

src/core/census/aggregation.h

src/core/census/context.c

src/core/census/context.h

src/core/census/grpc_context.c

src/core/census/grpc_filter.c

src/core/census/initialize.c

src/core/census/operation.c

src/core/census/tracing.c

src/core/channel/channel_args.c

src/core/channel/channel_args.h

src/core/channel/channel_stack.c

src/core/channel/channel_stack.h

src/core/channel/client_channel.c

src/core/channel/client_channel.h

src/core/channel/compress_filter.c

src/core/channel/connected_channel.c

src/core/channel/connected_channel.h

src/core/channel/context.h

src/core/channel/http_client_filter.c

src/core/channel/http_server_filter.c