Add a copy of the "WinClang64 (dbg)" bot to the main waterfall.

scripts/slave/recipes/chromium_trybot.expected/full_tryserver_chromium_win_win_clang.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\kill_processes.py"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "taskkill"
   },
@@ skipping 132 matching lines @@
   {
     "cmd": [
       "python",
       "-u",
       "[SLAVE_BUILD]\\src\\testing\\scripts\\get_compile_targets.py",
       "--output",
       "/path/to/tmp/json",
       "--",
       "--build-config-fs",
       "Debug_x64",
+      "--use-src-side-runtest-py",
       "--paths",
       "{\"checkout\": \"[SLAVE_BUILD]\\\\src\", \"runit.py\": \"RECIPE_PACKAGE_REPO[build]\\\\scripts\\\\tools\\\\runit.py\", \"runtest.py\": \"RECIPE_PACKAGE_REPO[build]\\\\scripts\\\\slave\\\\runtest.py\"}",
       "--properties",
       "{\"buildername\": \"win_clang\", \"buildnumber\": 571, \"mastername\": \"tryserver.chromium.win\", \"slavename\": \"TestSlavename\", \"target_platform\": \"win\"}"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "get compile targets for scripts",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output@{}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
-      "[SLAVE_BUILD]\\src\\testing\\buildbot\\chromium.fyi.json",
+      "[SLAVE_BUILD]\\src\\testing\\buildbot\\chromium.win.json",
       "/path/to/tmp/json"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "read test spec",
     "~followup_annotations": [
-      "@@@STEP_TEXT@path: [SLAVE_BUILD]\\src\\testing\\buildbot\\chromium.fyi.json@@@",
+      "@@@STEP_TEXT@path: [SLAVE_BUILD]\\src\\testing\\buildbot\\chromium.win.json@@@",
       "@@@STEP_LOG_LINE@json.output@{}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "cmd": [
       "RECIPE_PACKAGE_REPO[depot_tools]\\bootstrap\\win\\win_tools.bat"
     ],
     "cwd": "RECIPE_PACKAGE_REPO[depot_tools]",
     "name": "ensure git tooling on windows"
@@ skipping 170 matching lines @@
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "mark: before_tests"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]