harden and speed up path op unit tests

PathOps tests internal routines direcctly. Check to make sure that
test points, lines, quads, curves, triangles, and bounds read from
arrays are valid (i.e., don't contain NaN) before calling the
test function.

Repurpose the test flags.
- make 'v' verbose test region output against path output
- make 'z' single threaded (before it made it multithreaded)

The latter change speeds up tests run by the buildbot by 2x to 3x.

BUG=

Review URL: https://codereview.chromium.org/19374003

git-svn-id: http://skia.googlecode.com/svn/trunk@10107 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/skia_test.cpp b/tests/skia_test.cpp
index dc1015d..da63d42 100644
--- a/tests/skia_test.cpp
+++ b/tests/skia_test.cpp
@@ -125,7 +125,7 @@
 DEFINE_string2(tmpDir, t, NULL, "tmp directory for tests to use.");
 DEFINE_string2(resourcePath, i, NULL, "directory for test resources.");
 DEFINE_bool2(extendedTest, x, false, "run extended tests for pathOps.");
-DEFINE_bool2(threaded, z, false, "allow tests to use multiple threads internally.");
+DEFINE_bool2(single, z, false, "run tests on a single thread internally.");
 DEFINE_bool2(verbose, v, false, "enable verbose output.");
 DEFINE_int32(threads, SkThreadPool::kThreadPerCore,
              "Run threadsafe tests on a threadpool with this many threads.");
@@ -237,7 +237,7 @@
         SkDebugf("%s\n", header.c_str());
     }
 
-    DebugfReporter reporter(FLAGS_extendedTest, FLAGS_threaded, FLAGS_verbose);
+    DebugfReporter reporter(FLAGS_extendedTest, !FLAGS_single, FLAGS_verbose);
     Iter iter(&reporter);
 
     // Count tests first.