Only have featureFlag attr in xml when v>baklava

This makes it so that if there are xml files that use the featureFlag
attribute they are split into a pre-B file where all flags are assumed
false and a B version that is the file as is.

Test: Automation
Bug: 377974898
Flag: android.content.res.layout_readwrite_flags
Change-Id: Iab1a69a6d0b3e7efd7033887c351430fb2aabd19
diff --git a/tools/aapt2/Android.bp b/tools/aapt2/Android.bp
index f43cf52..43d5b71 100644
--- a/tools/aapt2/Android.bp
+++ b/tools/aapt2/Android.bp
@@ -113,6 +113,7 @@
         "io/ZipArchive.cpp",
         "link/AutoVersioner.cpp",
         "link/FeatureFlagsFilter.cpp",
+        "link/FlaggedXmlVersioner.cpp",
         "link/FlagDisabledResourceRemover.cpp",
         "link/ManifestFixer.cpp",
         "link/NoDefaultResourceRemover.cpp",