Remove pre-aidegen IDE support logic

This has apparently been racy ever since
https://android-review.googlesource.com/c/platform/build/+/971925
and isn't generally useful anymore, as aidegen has taken over.

Bug: 193095826
Test: treehugger
Change-Id: I09b6b340b84d1476a574b302db520210561a4e5e
diff --git a/CleanSpec.mk b/CleanSpec.mk
index 3beadff..e96735b 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -757,6 +757,9 @@
 # vendor-ramdisk renamed to vendor_ramdisk
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/vendor-ramdisk)
 
+# Common R directory has been removed.
+$(call add-clean-step, rm -rf $(OUT_DIR)/target/common/R)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************