Make hiddenapi gtest host-only

The tool itself is meant to be used while building boot class path
dex files. No point in running it on target.

Bug: 64382372
Test: m test-art-target-gtest
Change-Id: Ieb0a2f1dd22d035ed194abd5360925598c333616
diff --git a/tools/hiddenapi/Android.bp b/tools/hiddenapi/Android.bp
index ccab7f8..a78bc43 100644
--- a/tools/hiddenapi/Android.bp
+++ b/tools/hiddenapi/Android.bp
@@ -55,6 +55,8 @@
 
 art_cc_test {
     name: "art_hiddenapi_tests",
+    host_supported: true,
+    device_supported: false,
     defaults: [
         "art_gtest_defaults",
     ],