Perf sheriffing. <1% change in IO on moz page cycler.

tools/perf_expectations/perf_expectations.json

Index: tools/perf_expectations/perf_expectations.json
diff --git a/tools/perf_expectations/perf_expectations.json b/tools/perf_expectations/perf_expectations.json
index 97d672cd1179e3a99d7b155a6ff71b00ddde1555..266e0f62a26bdac39446a289876dbd43120a8a71 100644
--- a/tools/perf_expectations/perf_expectations.json
+++ b/tools/perf_expectations/perf_expectations.json
@@ -423,9 +423,9 @@
  "xp-release-dual-core/morejs/times/t": {"reva": 131574, "revb": 127228, "improve": -452, "regress": 456, "sha1": "21ef0dc0"},
  "xp-release-dual-core/moz/times/t": {"reva": 147678, "revb": 147799, "improve": -35, "regress": 61, "sha1": "0d686973"},
  "xp-release-dual-core/moz/total_byte_b/IO_b": {"reva": 147565, "revb": 148240, "improve": 176, "regress": 2496, "sha1": "5e972642"},
- "xp-release-dual-core/moz/total_byte_r/IO_r": {"reva": 148220, "revb": 148240, "improve": 358, "regress": 431, "sha1": "41aa8cef"},
+ "xp-release-dual-core/moz/total_byte_r/IO_r": {"reva": 148636, "revb": 148767, "improve": 253, "regress": 430, "sha1": "dfa2a845"},
  "xp-release-dual-core/moz/total_op_b/IO_op_b": {"reva": 141869, "revb": 142490, "improve": 169, "regress": 2089, "sha1": "2f018b43"},
- "xp-release-dual-core/moz/total_op_r/IO_op_r": {"reva": 148636, "revb": 148651, "improve": -188, "regress": -33, "sha1": "3891978b"},
+ "xp-release-dual-core/moz/total_op_r/IO_op_r": {"reva": 148636, "revb": 148767, "improve": -220, "regress": 136, "sha1": "fb000ffe"},
  "xp-release-dual-core/moz/vm_peak_b/vm_pk_b": {"reva": 137781, "revb": 138227, "improve": -1565492, "regress": 2464359, "sha1": "0e00a85f"},
  "xp-release-dual-core/moz/vm_peak_r/vm_pk_r": {"reva": 148248, "revb": 148263, "improve": -2468660, "regress": 79349760, "sha1": "c3a017fe"},
  "xp-release-dual-core/startup/warm/t": {"reva": 76825, "revb": 77094, "improve": -107, "regress": 141, "sha1": "e0dcf672"},