Update idmap2_tests to really work host-side

idmap2_tests is marked host_supported:true but use
a AndroidTest.xml config that can only work for device.

Deleting the explict config to rely on the auto-gen ones.
Adding unit_tests:true to run in presubmit

Test: presubmit, atest idmap2_tests --host
Bug: 179092189
Change-Id: I0b325abc6ce7fc6c777d070bb0fc0e9e8a7cdedd
diff --git a/cmds/idmap2/Android.bp b/cmds/idmap2/Android.bp
index e21a6b2..50f4001 100644
--- a/cmds/idmap2/Android.bp
+++ b/cmds/idmap2/Android.bp
@@ -132,9 +132,6 @@
         "tests/XmlParserTests.cpp",
         "tests/ZipFileTests.cpp",
     ],
-    required: [
-        "idmap2",
-    ],
     static_libs: ["libgmock"],
     target: {
         android: {
@@ -163,9 +160,19 @@
             shared_libs: [
                 "libz",
             ],
+            data: [
+                ":libz",
+                ":idmap2",
+            ],
         },
     },
-    data: ["tests/data/**/*.apk"],
+    data: [
+        "tests/data/**/*.apk",
+    ],
+    compile_multilib: "first",
+    test_options: {
+        unit_test: true,
+    },
 }
 
 cc_binary {