scons: Get rid of some redundant text in a print out.
scons: Get rid of some redundant text in a print out.

When printing the LSAN_OPTIONS setting to use, we were manually
prefixing "suppressions=" to it, but it already had that built into the
option. This made that text print twice. Remove the duplicate.

Change-Id: Ie599e02d0cf17bcf18278d72350831a2e0ac09f6
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48644
Reviewed-by: Bobby R. Bruce <b9dba908ffb6c6d8ffe449cc88b3709c13c485c2@ucdavis.edu>
Maintainer: Bobby R. Bruce <b9dba908ffb6c6d8ffe449cc88b3709c13c485c2@ucdavis.edu>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

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