apex supports ".apex" tag

Tests can embed non-compressed .apex output with the tag.

Bug: 221024307
Test: soong test
Change-Id: Id4a239d1897237105a064cea8c97029f5b996a98
diff --git a/apex/builder.go b/apex/builder.go
index fc4bf8a..183c215 100644
--- a/apex/builder.go
+++ b/apex/builder.go
@@ -810,6 +810,9 @@
 		Implicits:   implicits,
 		Args:        args,
 	})
+	if suffix == imageApexSuffix {
+		a.outputApexFile = signedOutputFile
+	}
 	a.outputFile = signedOutputFile
 
 	if ctx.ModuleDir() != "system/apex/apexd/apexd_testdata" && a.testOnlyShouldForceCompression() {