message: config: update check tool bazel target
  This change creates a cc_test_lib to be consumable by the binary rule here, and other consumers that want to recompile with private filters.
diff: @@ -3,14 +3,20 @@ licenses(["notice"]) # Apache 2
  load(
  "//bazel:envoy_build_system.bzl",
  "envoy_cc_binary",
  + "envoy_cc_test_library",
  "envoy_package",
  )
  envoy_package()
  +envoy_cc_test_library(
  + name = "config_load_check_lib",
  + srcs = ["config_load_check.cc"],
  + deps = ["//test/config_test:config_test_lib"],
  +)
  +
  envoy_cc_binary(
  name = "config_load_check_tool",
  testonly = 1,
  - srcs = ["config_load_check.cc"],
  - deps = ["//test/config_test:config_test_lib"],
  + deps = [":config_load_check_lib"],
  )
  