Use empty string for core image variant

Use the empty string for the core image variant so that modules
added to imageMutator do not change their build directory.

Bug: 142286466
Test: m checkbuild
Change-Id: Ida4534d9a4d6176236aaa480fed359ce27acfaa1
Merged-In: Ida4534d9a4d6176236aaa480fed359ce27acfaa1
(cherry picked from commit 72d685ee7f45e5393be44ae4159edf083ac918de)
diff --git a/android/image.go b/android/image.go
index 8424cf8..5291ce3 100644
--- a/android/image.go
+++ b/android/image.go
@@ -42,7 +42,7 @@
 	// CoreVariation is the variant used for framework-private libraries, or
 	// SDK libraries. (which framework-private libraries can use), which
 	// will be installed to the system image.
-	CoreVariation string = "core"
+	CoreVariation string = ""
 
 	// RecoveryVariation means a module to be installed to recovery image.
 	RecoveryVariation string = "recovery"
diff --git a/android/prebuilt_etc_test.go b/android/prebuilt_etc_test.go
index 6bb3ccf..3c466a1 100644
--- a/android/prebuilt_etc_test.go
+++ b/android/prebuilt_etc_test.go
@@ -88,7 +88,7 @@
 		}
 	`)
 
-	p := ctx.ModuleForTests("foo.conf", "android_arm64_armv8-a_core").Module().(*PrebuiltEtc)
+	p := ctx.ModuleForTests("foo.conf", "android_arm64_armv8-a").Module().(*PrebuiltEtc)
 	if p.outputFilePath.Base() != "foo.installed.conf" {
 		t.Errorf("expected foo.installed.conf, got %q", p.outputFilePath.Base())
 	}
@@ -107,12 +107,12 @@
 		}
 	`)
 
-	p := ctx.ModuleForTests("my_foo", "android_arm64_armv8-a_core").Module().(*PrebuiltEtc)
+	p := ctx.ModuleForTests("my_foo", "android_arm64_armv8-a").Module().(*PrebuiltEtc)
 	if p.outputFilePath.Base() != "my_foo" {
 		t.Errorf("expected my_foo, got %q", p.outputFilePath.Base())
 	}
 
-	p = ctx.ModuleForTests("my_bar", "android_arm64_armv8-a_core").Module().(*PrebuiltEtc)
+	p = ctx.ModuleForTests("my_bar", "android_arm64_armv8-a").Module().(*PrebuiltEtc)
 	if p.outputFilePath.Base() != "bar.conf" {
 		t.Errorf("expected bar.conf, got %q", p.outputFilePath.Base())
 	}
@@ -141,7 +141,7 @@
 		"LOCAL_TARGET_REQUIRED_MODULES": {"targetModA"},
 	}
 
-	mod := ctx.ModuleForTests("foo", "android_arm64_armv8-a_core").Module().(*PrebuiltEtc)
+	mod := ctx.ModuleForTests("foo", "android_arm64_armv8-a").Module().(*PrebuiltEtc)
 	entries := AndroidMkEntriesForTest(t, config, "", mod)[0]
 	for k, expectedValue := range expected {
 		if value, ok := entries.EntryMap[k]; ok {
@@ -178,7 +178,7 @@
 		}
 	`)
 
-	p := ctx.ModuleForTests("foo.conf", "android_arm64_armv8-a_core").Module().(*PrebuiltEtc)
+	p := ctx.ModuleForTests("foo.conf", "android_arm64_armv8-a").Module().(*PrebuiltEtc)
 	expected := buildDir + "/target/product/test_device/system/usr/share/bar"
 	if p.installDirPath.String() != expected {
 		t.Errorf("expected %q, got %q", expected, p.installDirPath.String())
@@ -210,7 +210,7 @@
 		}
 	`)
 
-	p := ctx.ModuleForTests("foo.conf", "android_arm64_armv8-a_core").Module().(*PrebuiltEtc)
+	p := ctx.ModuleForTests("foo.conf", "android_arm64_armv8-a").Module().(*PrebuiltEtc)
 	expected := buildDir + "/target/product/test_device/system/fonts"
 	if p.installDirPath.String() != expected {
 		t.Errorf("expected %q, got %q", expected, p.installDirPath.String())
@@ -245,7 +245,7 @@
 	for _, tt := range tests {
 		t.Run(tt.description, func(t *testing.T) {
 			ctx, _ := testPrebuiltEtc(t, tt.config)
-			p := ctx.ModuleForTests("foo.conf", "android_arm64_armv8-a_core").Module().(*PrebuiltEtc)
+			p := ctx.ModuleForTests("foo.conf", "android_arm64_armv8-a").Module().(*PrebuiltEtc)
 			if p.installDirPath.String() != tt.expectedPath {
 				t.Errorf("expected %q, got %q", tt.expectedPath, p.installDirPath)
 			}