Server fuzzer progress

Makefile

build.yaml

test/core/end2end/fuzzers/server_fuzzer.c

test/core/util/mock_endpoint.c

test/core/util/mock_endpoint.h

tools/run_tests/sources_and_headers.json

tools/run_tests/tests.json

vsprojects/vcxproj/grpc_test_util/grpc_test_util.vcxproj

...cts/vcxproj/grpc_test_util/grpc_test_util.vcxproj.filters

...j/grpc_test_util_unsecure/grpc_test_util_unsecure.vcxproj

...est_util_unsecure/grpc_test_util_unsecure.vcxproj.filters