Remove AfdoAdditionalProfileDirs product variable

AfdoAdditionalProfileDirs is unconnected to build/make/core/soong_config.mk and is currently unused. Removing AfdoAdditionalProfileDirs will cut down on complexity when we migrate the support of auto-fdo profiles to Bazel cc rules.

b/258684450 proposes an alternative to support the use cases that were meant to be supported by AfdoAdditionalProfileDirs.

Test: existing go tests
Bug: 253540178
Change-Id: I024e48598a560717a1d6c19b16bde3fe65ff1961
diff --git a/android/variable.go b/android/variable.go
index 37ecab5..28f22c9 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -336,8 +336,7 @@
 
 	NamespacesToExport []string `json:",omitempty"`
 
-	AfdoAdditionalProfileDirs []string `json:",omitempty"`
-	PgoAdditionalProfileDirs  []string `json:",omitempty"`
+	PgoAdditionalProfileDirs []string `json:",omitempty"`
 
 	VndkUseCoreVariant         *bool `json:",omitempty"`
 	VndkSnapshotBuildArtifacts *bool `json:",omitempty"`