ART: Make kDebugVerifier a verbose flag

To aid in debugging efforts, finally introduce a verifier-debug
verbose-logging flag that takes over the compile-time kDebugVerifier
flag.

Collecting verification times from a well-known large app during
dex2oat via dump-timings shows a difference in the noise.

Logging of the steps is restricted to failure cases, to avoid
spam.

Test: m
Test: m test-art-host
Test: manual: dex2oat --runtime-arg -verbose:verifier-debug APK with failures
Change-Id: Icb998cc42a531b80f20f986625869505271b7c98
diff --git a/cmdline/cmdline_types.h b/cmdline/cmdline_types.h
index 37bdcdc..f12ef97 100644
--- a/cmdline/cmdline_types.h
+++ b/cmdline/cmdline_types.h
@@ -669,6 +669,8 @@
         log_verbosity.threads = true;
       } else if (verbose_options[j] == "verifier") {
         log_verbosity.verifier = true;
+      } else if (verbose_options[j] == "verifier-debug") {
+        log_verbosity.verifier_debug = true;
       } else if (verbose_options[j] == "image") {
         log_verbosity.image = true;
       } else if (verbose_options[j] == "systrace-locks") {