first step in transforming grpclb_test to C++

Makefile

build.yaml

test/cpp/grpclb/grpclb_test.cc

tools/run_tests/sources_and_headers.json

tools/run_tests/tests.json

vsprojects/buildtests_c.sln

vsprojects/vcxproj/grpc_test_util/grpc_test_util.vcxproj

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

vsprojects/vcxproj/test/grpclb_test/grpclb_test.vcxproj

...ects/vcxproj/test/grpclb_test/grpclb_test.vcxproj.filters