mainline_modules_sdks: Remove legacy build support

This change will stop building the following directories:
* mainline-sdks/current
* stubs

Bug: 204763318
Test: packages/modules/common/build/mainline_modules_sdks.sh
Change-Id: I9ed17ff472bfd36d1b5baa365ba33b9e2e283412

build/mainline_modules_sdks.py

@@ -485,36 +485,6 @@ def create_latest_sdk_snapshots(build_release: BuildRelease,
     producer.produce_bundled_dist_for_build_release(build_release, modules)
 
 
-def create_legacy_dist_structures(build_release: BuildRelease,
-                                  producer: "SdkDistProducer",
-                                  modules: List["MainlineModule"]):
-    """Creates legacy file structures."""
-
-    # Only put unbundled modules in the legacy dist and stubs structures.
-    modules = [m for m in modules if not m.is_bundled()]
-
-    snapshots_dir = producer.produce_unbundled_dist_for_build_release(
-        build_release, modules)
-
-    # Create the out/dist/mainline-sdks/stubs structure.
-    # TODO(b/199759953): Remove stubs once it is no longer used by gantry.
-    # Clear and populate the stubs directory.
-    dist_dir = producer.dist_dir
-    stubs_dir = os.path.join(dist_dir, "stubs")
-    shutil.rmtree(stubs_dir, ignore_errors=True)
-
-    for module in modules:
-        apex = module.apex
-        dest_dir = os.path.join(dist_dir, "stubs", apex)
-        for sdk in module.sdks:
-            # If the sdk's name ends with -sdk then extract sdk library
-            # related files from its zip file.
-            if sdk.endswith("-sdk"):
-                sdk_file = sdk_snapshot_zip_file(snapshots_dir, sdk, "current")
-                extract_matching_files_from_zip(sdk_file, dest_dir,
-                                                sdk_library_files_pattern())
-
-
 Q = BuildRelease(
     name="Q",
     # At the moment we do not generate a snapshot for Q.
@@ -546,8 +516,7 @@ Tiramisu = BuildRelease(
 # before LATEST.
 
 # The build release for the latest build supported by this build, i.e. the
-# current build. This must be the last BuildRelease defined in this script,
-# before LEGACY_BUILD_RELEASE.
+# current build. This must be the last BuildRelease defined in this script.
 LATEST = BuildRelease(
     name="latest",
     creator=create_latest_sdk_snapshots,
@@ -556,20 +525,6 @@ LATEST = BuildRelease(
     soong_env={},
 )
 
-# The build release to populate the legacy dist structure that does not specify
-# a particular build release. This MUST come after LATEST so that it includes
-# all the modules for which sdk snapshot source is available.
-LEGACY_BUILD_RELEASE = BuildRelease(
-    name="legacy",
-    # There is no build release specific sub directory.
-    sub_dir="",
-    # Create snapshots needed for legacy tools.
-    creator=create_legacy_dist_structures,
-    # There are no build release specific environment variables to pass to
-    # Soong.
-    soong_env={},
-)
-
 
 @dataclasses.dataclass(frozen=True)
 class SdkLibrary: