Platform mapping-based product config

This allows us to set product variables as build settings instead
of loading them from a target's provider, which further allows us
to read product config variables in transitions.

Bug: 287539062
Bug: 269577299
Test: Presubmits
Change-Id: I8497703f706162572ceb3486240e1eb02a37f5f6
diff --git a/android/sdk_version_test.go b/android/sdk_version_test.go
index ea99c4d..30bd002 100644
--- a/android/sdk_version_test.go
+++ b/android/sdk_version_test.go
@@ -75,7 +75,7 @@
 
 	config := NullConfig("", "")
 
-	config.productVariables = productVariables{
+	config.productVariables = ProductVariables{
 		Platform_sdk_version:              intPtr(31),
 		Platform_sdk_codename:             stringPtr("Tiramisu"),
 		Platform_version_active_codenames: []string{"Tiramisu"},