gm: display summary of all results by ErrorType

gm/tests/outputs/compared-against-different-pixels-images/output-expected/stdout

Index: gm/tests/outputs/compared-against-different-pixels-images/output-expected/stdout
===================================================================
--- gm/tests/outputs/compared-against-different-pixels-images/output-expected/stdout	(revision 8399)
+++ gm/tests/outputs/compared-against-different-pixels-images/output-expected/stdout	(working copy)
@@ -1,3 +1,9 @@
 GM: reading from gm/tests/inputs/images/different-pixels
 GM: drawing... selftest1 [300 200]
-GM: Ran 1 tests: 0 passed, 1 failed, 0 missing reference images
+GM: Ran 1 GMs, each with 2 configs ["8888", "565"] and 7 modes ["replay", "serialize", "rtree", "tileGrid1.000000", "pipe", "pipe cross-process", "pipe cross-process, shared address"], so there should be a total of 9 tests

[borenet, 2013/03/29 05:55:14]

This is very wordy...

[epoger, 2013/04/02 16:00:14]

Agreed.  What do you think it should look like?  Should we rearrange the
information, or leave some of it out?

If you tell me what you think this output should look like, I'll make it happen
in this CL.

[borenet, 2013/04/02 16:17:56]

I don't know how helpful the above information is.  I guess it's primarily for
the self-test?  It might help just to add some line breaks:

GM: Ran 1 GMs
GM: ... over 2 configs ["8888", "565"]
GM: ... and 7 modes [...]
GM: ... for a total of 9 tests.

What is the value of the following line ("Ran 9 tests...")?  It seems that the
"9 tests" is given above, and the falures for each type is given below.

[epoger, 2013/04/03 04:18:23]

Actually, no... I wanted to make it easier to notice problems such as
https://code.google.com/p/skia/issues/detail?id=1180 ('image-surface gm test is
failing in "deferred" mode, and gm is not reporting the failure'): types of
tests that the caller ASSUMES are being run by gm, but may not be!

(Looking at this output, you can now tell that gm is not running in deferred
mode, which is a bug as noted above!)

In patchset 6, I split up this single summary line as you suggested. 
Personally, I prefer it all in one line (so it's easier to filter it with grep),
but I'm fine either way.
To help catch another type of bug: a particular test which runs for MOST gms but
not ALL.  See "Ultimately, we should signal an error" TODO in gmmain.cpp.

+GM: Ran 9 tests: NoGpuContext=0 ImageMismatch=2 MissingExpectations=0 WritingReferenceImage=0
+GM: [*] 0 NoGpuContext:
+GM: [*] 2 ImageMismatch: 8888/selftest1 565/selftest1
+GM: [ ] 0 MissingExpectations:
+GM: [*] 0 WritingReferenceImage:
+GM: (results marked with [*] will cause nonzero return value)