Skip TestDex2oatToolDeps on Darwin.

This fixes https://r.android.com/1711292.

Test: m nothing
Bug: 188647117
Bug: 145934348
Bug: 172480615
Change-Id: I0c80b546a814d799562f374148eae5ca23b0e1f8

java/dexpreopt_test.go

@@ -173,6 +173,11 @@ func enabledString(enabled bool) string {
 }
 
 func TestDex2oatToolDeps(t *testing.T) {
+	if android.BuildOs != android.Linux {
+		// The host binary paths checked below are build OS dependent.
+		t.Skipf("Unsupported build OS %s", android.BuildOs)
+	}
+
 	preparers := android.GroupFixturePreparers(
 		cc.PrepareForTestWithCcDefaultModules,
 		PrepareForTestWithJavaDefaultModulesWithoutFakeDex2oatd,