DM: failure to canary a sink is now fatal.

This requires we remove NVPR from the default set of configs, as we only find
out at runtime that it's not available.  All the other defaults will either be
compiled in and supported, or not compiled in and non-fatally skipped as
unknown configs.

BUG=skia:

Review URL: https://codereview.chromium.org/1100773003
diff --git a/dm/DM.cpp b/dm/DM.cpp
index ff9dc57..c0fccaa 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -300,8 +300,8 @@
     SkString log;
     Error err = sink->draw(noop, &bitmap, &stream, &log);
     if (err.isFatal()) {
-        SkDebugf("Skipping %s: %s\n", tag, err.c_str());
-        return;
+        SkDebugf("Could not run %s: %s\n", tag, err.c_str());
+        exit(1);
     }
 
     Tagged<Sink>& ts = gSinks.push_back();