Make OutDir() and SoongOutDir() be consistent.

They both used to return out/soong. Unfortunately, the tests seem to
assume the old behavior, so I had to keep tests inconsistent and I was
scared of dexpreopt, too.

Test: Presubmits.
Change-Id: Ib00c7956fd2cdb28cc11d481c17e5a3ff5ad563a
diff --git a/dexpreopt/dexpreopt_gen/dexpreopt_gen.go b/dexpreopt/dexpreopt_gen/dexpreopt_gen.go
index 7dbe74c..ba05d94 100644
--- a/dexpreopt/dexpreopt_gen/dexpreopt_gen.go
+++ b/dexpreopt/dexpreopt_gen/dexpreopt_gen.go
@@ -87,7 +87,9 @@
 		usage("--module configuration file is required")
 	}
 
-	ctx := &builderContext{android.NullConfig(*outDir)}
+	// NOTE: duplicating --out_dir here is incorrect (one should be the another
+	// plus "/soong" but doing so apparently breaks dexpreopt
+	ctx := &builderContext{android.NullConfig(*outDir, *outDir)}
 
 	globalSoongConfigData, err := ioutil.ReadFile(*globalSoongConfigPath)
 	if err != nil {