Revert "Implement mixed builds for apex modules."

Revert submission 2147387-mixed_builds

Reason for revert: Breaks zipapex build on git_master-art-host
Bug: 239925080
Reverted Changes:
I9f1e03e5e:Implement mixed builds for apex modules.
I13d9a0270:Add container and bundle encription key pairs to t...

Change-Id: I0eaad4dd81cac16d634f4c9cec18137a38e30d47
diff --git a/bazel/aquery.go b/bazel/aquery.go
index 418b143..ae2b107 100644
--- a/bazel/aquery.go
+++ b/bazel/aquery.go
@@ -574,7 +574,7 @@
 
 // expandTemplateContent substitutes the tokens in a template.
 func expandTemplateContent(actionEntry action) string {
-	var replacerString []string
+	replacerString := []string{}
 	for _, pair := range actionEntry.Substitutions {
 		value := pair.Value
 		if val, ok := templateActionOverriddenTokens[pair.Key]; ok {
@@ -647,7 +647,7 @@
 		}
 		labels = append([]string{currFragment.Label}, labels...)
 		if currId == currFragment.ParentId {
-			return "", fmt.Errorf("fragment cannot refer to itself as parent %#v", currFragment)
+			return "", fmt.Errorf("Fragment cannot refer to itself as parent %#v", currFragment)
 		}
 		currId = currFragment.ParentId
 	}