Merging 18 commit(s) from Chromium's toolchain-utils

Merged commit digest:
  22e3075 compiler_wrapper: Use syscall.exec on platforms other than Chrome OS
  43c9066 toolchain-utils: migrate all in-use projects to python 3
  c4615d1 compiler_wrapper: update the presubmit tests.
  8477fef crosperf: change skylab credential location in sheriff_utils
  cc2dc33 bisection: fix an error message
  6ba0188 toolchain-utils: deprecate cwp and mem_tests scripts
  7bda3eb toolchain-utils: move no longer used scripts to deprecated
  81d651f toolchain-utils: Partially port scripts to python 3
  4b68aee afdo_metadata: Publish new profiles for kernel 4.4.
  07a42cb cros_utils: fix imports in cros_utils
  b02958e toolchain-utils: fix bug in moving weekday testing to nightly-testing.
  05c0470 toolchain-utils: port binary_search_tool to python3
  172ccc1 afdo_metadata: Publish new profiles for kernel 3.18.
  be756e0 toolchain-utils: move weekday testing into nightly-testing dir.
  d820cda crosperf: introduce new test_that and skylab run for suite_runner
  00156ea cros_utils: add x20 email sending functionality
  d89779d binary_search_tool: fix failures in presubmit
  145952b compiler_wrapper: add update_compiler_wrapper.sh

Change-Id: I3cc54b1331bf8362aae5e8f87eabfdb1377383ef