Temporarily disable lb policies test

Makefile

@@ -1860,8 +1860,6 @@ test_c: buildtests_c
 
 
 flaky_test_c: buildtests_c
-	$(E) "[RUN]     Testing lb_policies_test"
-	$(Q) $(BINDIR)/$(CONFIG)/lb_policies_test || ( echo test lb_policies_test failed ; exit 1 )
 	$(E) "[RUN]     Testing mlog_test"
 	$(Q) $(BINDIR)/$(CONFIG)/mlog_test || ( echo test mlog_test failed ; exit 1 )
 

build.yaml

@@ -2348,8 +2348,8 @@ targets:
   - gpr
 - name: lb_policies_test
   cpu_cost: 0.1
-  flaky: true
   build: test
+  run: false
   language: c
   src:
   - test/core/client_channel/lb_policies_test.c

tools/run_tests/generated/tests.json

@@ -1521,28 +1521,6 @@
       "windows"
     ]
   }, 
-  {
-    "args": [], 
-    "ci_platforms": [
-      "linux", 
-      "mac", 
-      "posix", 
-      "windows"
-    ], 
-    "cpu_cost": 0.1, 
-    "exclude_configs": [], 
-    "exclude_iomgrs": [], 
-    "flaky": true, 
-    "gtest": false, 
-    "language": "c", 
-    "name": "lb_policies_test", 
-    "platforms": [
-      "linux", 
-      "mac", 
-      "posix", 
-      "windows"
-    ]
-  }, 
   {
     "args": [], 
     "ci_platforms": [