health AIDL: add vts tests

This is a direct translation of the health 2.0
and 2.1 VTS tests.

Some slight modifications are made (e.g. use googlemock
matchers) to make the test code more readable.

Test: run on Pixel
Bug: 203245778

Change-Id: Ifc3799a04a6a09d0d53f400b60d19fbfe004a3e3
diff --git a/health/2.0/vts/functional/Android.bp b/health/2.0/vts/functional/Android.bp
index eb69612..0fcac19 100644
--- a/health/2.0/vts/functional/Android.bp
+++ b/health/2.0/vts/functional/Android.bp
@@ -32,5 +32,11 @@
         "android.hardware.health@1.0",
         "android.hardware.health@2.0",
     ],
-    test_suites: ["general-tests", "vts"],
+    header_libs: [
+        "libhealthtest_headers",
+    ],
+    test_suites: [
+        "general-tests",
+        "vts",
+    ],
 }