fix: clear build cache in sync build-in-source test tearDown for reliable reruns (#8745)

The tearDown in TestSyncInfra_BuildInSource_Makefile and
TestSyncCode_BuildInSource_Makefile deletes the Makefile-created marker
files but does not invalidate the SAM build cache inside the temp test
data directory. On pytest reruns, SAM finds a valid cache and skips
re-running the Makefile, so the marker files are never recreated and
the file-existence assertion fails.

Clear .aws-sam inside test_data_path in tearDown so the build cache is
invalidated and the Makefile re-executes on retries.

Author: bnusunny

tests/integration/sync/test_sync_build_in_source.py

@@ -33,6 +33,9 @@ def tearDown(self):
             if os.path.isfile(path):
                 os.remove(path)
 
+        # Clear the build cache so reruns re-execute the Makefile and recreate marker files
+        shutil.rmtree(self.test_data_path.joinpath(".aws-sam"), ignore_errors=True)
+
     @parameterized.expand(
         [
             (True, True),  # build in source
@@ -94,6 +97,9 @@ def tearDown(self):
             if os.path.isfile(path):
                 os.remove(path)
 
+        # Clear the build cache so reruns re-execute the Makefile and recreate marker files
+        shutil.rmtree(Path(self.test_data_path, ".aws-sam"), ignore_errors=True)
+
     @parameterized.expand(
         [
             (True, True),  # build in source