Implement mixed builds for apex modules, take 2.

* Add ApexCqueryInfo to obtain apex artifacts used by the makefile
  generator and downstream modules
* Refactor code common to GenerateAndroidBuildActions and ProcessBazelQueryResponse
* Implement android.MixedBuildBuildable for modules
* Enable mixed build for apex modules with payload_type:"image"

The first take 6a2b7c40b was setting compressed APEX suffix incorrectly, and
was reverted in 8a3c91494.

Fixes: 239925080 239695521 232085015
Test: treehugger
Change-Id: I1720f8db3c7cc773183d25a815d9b7eeaf7c73ad

bazel/aquery.go

@@ -574,7 +574,7 @@ func (a *aqueryArtifactHandler) getOutputPaths(actionEntry action) (outputPaths
 
 // expandTemplateContent substitutes the tokens in a template.
 func expandTemplateContent(actionEntry action) string {
-	replacerString := []string{}
+	var replacerString []string
 	for _, pair := range actionEntry.Substitutions {
 		value := pair.Value
 		if val, ok := templateActionOverriddenTokens[pair.Key]; ok {
@@ -647,7 +647,7 @@ func expandPathFragment(id pathFragmentId, pathFragmentsMap map[pathFragmentId]p
 		}
 		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
 	}