Reorganize upb file structure

This change moves almost everything in the `upb/` directory up one level, so
that for example `upb/upb/generated_code_support.h` becomes just
`upb/generated_code_support.h`. The only exceptions I made to this were that I
left `upb/cmake` and `upb/BUILD` where they are, mostly because that avoids
conflict with other files and the current locations seem reasonable for now.

The `python/` directory is a little bit of a challenge because we had to merge
the existing directory there with `upb/python/`. I made `upb/python/BUILD` into
the BUILD file for the merged directory, and it effectively loads the contents
of the other BUILD file via `python/build_targets.bzl`, but I plan to clean
this up soon.

PiperOrigin-RevId: 568651768

Author: acozzette

.github/BUILD.bazel

@@ -6,26 +6,29 @@
 # of Xcode.
 xcode_version(
     name = "version14_2_14C18",
-    version = "14.2.14C18",
     aliases = ["14C18"],
     default_ios_sdk_version = "16.2",
-    default_tvos_sdk_version = "16.1",
     default_macos_sdk_version = "13.1",
+    default_tvos_sdk_version = "16.1",
     default_watchos_sdk_version = "9.1",
+    version = "14.2.14C18",
 )
 
 xcode_version(
     name = "version14_1_0_14B47b",
-    version = "14.1.0.14B47b",
     aliases = ["14B47b"],
     default_ios_sdk_version = "16.1",
-    default_tvos_sdk_version = "16.1",
     default_macos_sdk_version = "13.0",
+    default_tvos_sdk_version = "16.1",
     default_watchos_sdk_version = "9.1",
+    version = "14.1.0.14B47b",
 )
 
 xcode_config(
     name = "host_xcodes",
-    versions = [":version14_2_14C18", ":version14_1_0_14B47b"],
     default = ":version14_1_0_14B47b",
+    versions = [
+        ":version14_2_14C18",
+        ":version14_1_0_14B47b",
+    ],
 )

.github/workflows/test_python.yml

@@ -20,7 +20,7 @@ jobs:
         version: ["3.8", "3.9", "3.10", "3.11" ]
         include:
           - type: Pure
-            targets: //python/... //upb/python/... //python:python_version_test
+            targets: //python/... //python:python_version_test
             flags: --define=use_fast_cpp_protos=false
           - type: C++
             targets: //python/... //python:python_version_test
@@ -46,6 +46,7 @@ jobs:
           credentials: ${{ secrets.GAR_SERVICE_ACCOUNT }}
           bazel-cache: python_linux/${{ matrix.type }}_${{ matrix.version }}
           bazel: test ${{ matrix.targets }} ${{ matrix.flags }} --test_env=KOKORO_PYTHON_VERSION
+          exclude-targets: -//python/pb_unit_tests/...
 
 
   macos:
@@ -57,7 +58,7 @@ jobs:
         version: [ "3.11" ]
         include:
           - type: Pure
-            targets: //python/... //upb/python/... //python:python_version_test
+            targets: //python/... //python:python_version_test
           - type: C++
             targets: //python/... //python:python_version_test
             flags: --define=use_fast_cpp_protos=true
@@ -95,3 +96,4 @@ jobs:
             test ${{ matrix.targets }} ${{ matrix.flags }}
             --test_env=KOKORO_PYTHON_VERSION=${{ matrix.version }}
             --macos_minimum_os=10.9
+          exclude-targets: -//python/pb_unit_tests/...