gm self-test: stop checking stdout and stderr

gm/tests/outputs/no-hierarchy/output-expected/stdout

Index: gm/tests/outputs/no-hierarchy/output-expected/stdout
diff --git a/gm/tests/outputs/no-hierarchy/output-expected/stdout b/gm/tests/outputs/no-hierarchy/output-expected/stdout
deleted file mode 100644
index 2ae755a8b1f0f614d6f6fbb5548662259febfc57..0000000000000000000000000000000000000000
--- a/gm/tests/outputs/no-hierarchy/output-expected/stdout
+++ /dev/null
@@ -1,20 +0,0 @@
-GM: These configs will be run: 8888 565
-GM: reading expectations from JSON summary file gm/tests/inputs/json/different-pixels-no-hierarchy.json
-GM: writing to gm/tests/outputs/no-hierarchy/output-actual/writePath
-GM: writing mismatches to gm/tests/outputs/no-hierarchy/output-actual/mismatchPath
-GM: writing images without expectations to gm/tests/outputs/no-hierarchy/output-actual/missingExpectationsPath
-GM: reading resources from resources
-GM: drawing... selftest1 [300 200]
-GM: Ran 1 GMs
-GM: ... over  2 configs ["8888", "565"]
-GM: ...  and  1 modes   [""]
-GM: ... so there should be a total of 2 tests.
-GM: Ran 2 tests: NoGpuContext=0 IntentionallySkipped=0 RenderModeMismatch=0 GeneratePdfFailed=0 ExpectationsMismatch=2 MissingExpectations=0 WritingReferenceImage=0
-GM: [*] 0 NoGpuContext:
-GM: [ ] 0 IntentionallySkipped:
-GM: [*] 0 RenderModeMismatch:
-GM: [*] 0 GeneratePdfFailed:
-GM: [*] 2 ExpectationsMismatch: selftest1_8888 selftest1_565
-GM: [ ] 0 MissingExpectations:
-GM: [*] 0 WritingReferenceImage:
-GM: (results marked with [*] will cause nonzero return value)