make buildtests on windows pass

build.json

@@ -1361,6 +1361,9 @@
         "grpc",
         "gpr_test_util",
         "gpr"
+      ],
+      "platforms": [
+        "posix"
       ]
     },
     {

test/core/end2end/gen_build_json.py

@@ -101,7 +101,7 @@ def main():
               'language': 'c',
               'secure': 'check' if END2END_FIXTURES[f].secure else 'no',
               'src': ['test/core/end2end/fixtures/%s.c' % f],
-              'platforms': [ 'posix' ] if f.endswith('_posix') else [ 'windows', 'posix' ],
+              'platforms': [ 'posix' ] if f.endswith('_posix') else END2END_FIXTURES[f].platforms,
           }
           for f in sorted(END2END_FIXTURES.keys())] + [
           {

tools/run_tests/tests.json

@@ -353,7 +353,6 @@
     "language": "c", 
     "name": "httpcli_test", 
     "platforms": [
-      "windows", 
       "posix"
     ]
   },