Remove usages of long-form variables

The long-form variables (PRODUCTS.<makefile>.<variable>)
are used to get information about multiple products.
However, they've never really worked correctly, and so
importing multiple products is deprecated behavior.

Remove as many usages of the long-form variables and
multi-product imports as possible.

Bug: 228518445
Test: Manually
Change-Id: I0b67f16360ff8bdcdb39638de739440472bccf76
diff --git a/core/config.mk b/core/config.mk
index bd3d1a0..7af600f 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -1235,8 +1235,7 @@
 
 # These goals don't need to collect and include Android.mks/CleanSpec.mks
 # in the source tree.
-dont_bother_goals := out \
-    product-graph dump-products
+dont_bother_goals := out product-graph
 
 # Make ANDROID Soong config variables visible to Android.mk files, for
 # consistency with those defined in BoardConfig.mk files.