Disabling upb tests in python_cpp builds (#10392)

* Disabling upb tests in python_cpp builds

* Adding comment about upb

kokoro/linux/python310_cpp/continuous.cfg

@@ -11,7 +11,9 @@ env_vars {
 
 env_vars {
   key: "BAZEL_TARGETS"
-  value: "//python/... @upb//python/..."
+  # Note: upb tests don't work since the C++ extension takes precedence here.
+  # Note: upb tests don't work since the C++ extension takes precedence here.
+  value: "//python/..."
 }
 
 env_vars {

kokoro/linux/python310_cpp/presubmit.cfg

@@ -11,6 +11,7 @@ env_vars {
 
 env_vars {
   key: "BAZEL_TARGETS"
+  # Note: upb tests don't work since the C++ extension takes precedence here.
   value: "//python/..."
 }
 

kokoro/linux/python37_cpp/continuous.cfg

@@ -11,7 +11,8 @@ env_vars {
 
 env_vars {
   key: "BAZEL_TARGETS"
-  value: "//python/... @upb//python/..."
+  # Note: upb tests don't work since the C++ extension takes precedence here.
+  value: "//python/..."
 }
 
 env_vars {

kokoro/linux/python37_cpp/presubmit.cfg

@@ -11,6 +11,7 @@ env_vars {
 
 env_vars {
   key: "BAZEL_TARGETS"
+  # Note: upb tests don't work since the C++ extension takes precedence here.
   value: "//python/..."
 }
 

kokoro/linux/python38_cpp/continuous.cfg

@@ -11,7 +11,8 @@ env_vars {
 
 env_vars {
   key: "BAZEL_TARGETS"
-  value: "//python/... @upb//python/..."
+  # Note: upb tests don't work since the C++ extension takes precedence here.
+  value: "//python/..."
 }
 
 env_vars {

kokoro/linux/python38_cpp/presubmit.cfg

@@ -11,6 +11,7 @@ env_vars {
 
 env_vars {
   key: "BAZEL_TARGETS"
+  # Note: upb tests don't work since the C++ extension takes precedence here.
   value: "//python/..."
 }
 

kokoro/linux/python39_cpp/continuous.cfg

@@ -11,7 +11,8 @@ env_vars {
 
 env_vars {
   key: "BAZEL_TARGETS"
-  value: "//python/... @upb//python/..."
+  # Note: upb tests don't work since the C++ extension takes precedence here.
+  value: "//python/..."
 }
 
 env_vars {

kokoro/linux/python39_cpp/presubmit.cfg

@@ -11,6 +11,7 @@ env_vars {
 
 env_vars {
   key: "BAZEL_TARGETS"
+  # Note: upb tests don't work since the C++ extension takes precedence here.
   value: "//python/..."
 }