Exclude qps_test from tsan runs

The TSAN deadlock detector has some problems that prevents this test
from running successfully.

Issue #2994
  
An error occurred
 
 has been filed to re-enable these in the future.

build.json

@@ -2488,6 +2488,9 @@
         "gpr",
         "grpc++_test_config"
       ],
+      "exclude_configs": [
+        "tsan"
+      ],
       "platforms": [
         "mac",
         "linux",

templates/tools/run_tests/tests.json.template

@@ -6,6 +6,7 @@ ${json.dumps([{"name": tgt.name,
                "language": tgt.language,
                "platforms": tgt.platforms,
                "ci_platforms": tgt.ci_platforms,
+	       "exclude_configs": tgt.get("exclude_configs", []),
                "flaky": tgt.flaky}
               for tgt in targets
               if tgt.get('run', True) and tgt.build == 'test'],

tools/run_tests/run_tests.py

@@ -123,20 +123,19 @@ class CLanguage(object):
   def __init__(self, make_target, test_lang):
     self.make_target = make_target
     self.platform = platform_string()
-    with open('tools/run_tests/tests.json') as f:
+    self.test_lang = test_lang
-      js = json.load(f)
-      self.binaries = [tgt
-                       for tgt in js
-                       if tgt['language'] == test_lang and
-                          platform_string() in tgt['platforms']]
-      self.ci_binaries = [tgt
-                         for tgt in js
-                         if tgt['language'] == test_lang and
-                            platform_string() in tgt['ci_platforms']]
 
   def test_specs(self, config, travis):
     out = []
-    for target in (self.ci_binaries if travis else self.binaries):
+    with open('tools/run_tests/tests.json') as f:
+      js = json.load(f)
+      platforms_str = 'ci_platforms' if travis else 'platforms'
+      binaries = [tgt
+                  for tgt in js
+                  if tgt['language'] == self.test_lang and
+                      config.build_config not in tgt['exclude_configs'] and
+                      platform_string() in tgt[platforms_str]]
+    for target in binaries:
       if travis and target['flaky']:
         continue
       if self.platform == 'windows':