Revert "Use D8 by default for android_test"

This reverts commit 02edc1004757f6d6d5c2e2a93f1e8656ae2435cf.

Reason for revert: Breaks test_suites_x86_64_coverage

Bug: 233421462
Change-Id: I7b04d3fd7802be0f271ea3c29ef25e3d08ab1389
diff --git a/java/app.go b/java/app.go
index 8c5933a..768d9e9 100755
--- a/java/app.go
+++ b/java/app.go
@@ -1017,7 +1017,7 @@
 func AndroidTestFactory() android.Module {
 	module := &AndroidTest{}
 
-	module.Module.dexProperties.Optimize.EnabledByDefault = false
+	module.Module.dexProperties.Optimize.EnabledByDefault = true
 
 	module.Module.properties.Instrument = true
 	module.Module.properties.Supports_static_instrumentation = true
@@ -1071,7 +1071,6 @@
 func AndroidTestHelperAppFactory() android.Module {
 	module := &AndroidTestHelperApp{}
 
-	// TODO(b/192032291): Disable by default after auditing downstream usage.
 	module.Module.dexProperties.Optimize.EnabledByDefault = true
 
 	module.Module.properties.Installable = proptools.BoolPtr(true)
diff --git a/java/dex.go b/java/dex.go
index c943938..13d6e4a 100644
--- a/java/dex.go
+++ b/java/dex.go
@@ -36,8 +36,8 @@
 	Main_dex_rules []string `android:"path"`
 
 	Optimize struct {
-		// If false, disable all optimization.  Defaults to true for android_app and
-		// android_test_helper_app modules, false for android_test, java_library, and java_test modules.
+		// If false, disable all optimization.  Defaults to true for android_app and android_test
+		// modules, false for java_library and java_test modules.
 		Enabled *bool
 		// True if the module containing this has it set by default.
 		EnabledByDefault bool `blueprint:"mutated"`
diff --git a/java/java_test.go b/java/java_test.go
index 56a4248..4c93824 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -723,9 +723,9 @@
 		t.Errorf("atestNoOptimize should not optimize APK")
 	}
 
-	atestDefault := ctx.ModuleForTests("atestDefault", "android_common").MaybeRule("d8")
+	atestDefault := ctx.ModuleForTests("atestDefault", "android_common").MaybeRule("r8")
 	if atestDefault.Output == nil {
-		t.Errorf("atestDefault should not optimize APK")
+		t.Errorf("atestDefault should optimize APK")
 	}
 }