CHROMIUM: test_job_process: Exclude __LLVM_* variables from env test

Code coverage builders manage some profiling checks via the
__LLVM_PROFILE_RT_INIT_ONCE variable. Exclude the "__LLVM_" prefix from
any environment checks.

Resolves test failures that look like:

...with environment of unnamed instance
BAD: wrong content in file 0x59fbc44cd900 (output), expected eof got '__LLVM_PROFILE_RT_INIT_ONCE=__LLVM_PROFILE_RT_INIT_ONCE
'
	at tests/test_job_process.c:772 (test_start).

BUG=b:332653406, b:232122437
TEST=`FEATURES=test emerge-${BOARD} upstart`

Change-Id: I79262fff4747e0318e8a06d8d9cdf5084439f643
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/upstart/+/5431196
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Commit-Queue: Brian Norris <briannorris@chromium.org>
1 file changed