Add coverage flags to VTS light test.

Build test with coverage flags to support coverage measurement
at test time.

Test: pass
Bug: 32022457
Change-Id: Ia12f202900ecc243e43ed472c8609c2c7ccc3b4d
diff --git a/light/2.0/vts/functional/Android.bp b/light/2.0/vts/functional/Android.bp
index b290b59..edb5ca9 100644
--- a/light/2.0/vts/functional/Android.bp
+++ b/light/2.0/vts/functional/Android.bp
@@ -26,8 +26,12 @@
     ],
     static_libs: ["libgtest"],
     cflags: [
+        "--coverage",
         "-O0",
         "-g",
     ],
+    ldflags: [
+        "--coverage"
+    ]
 }