For sanitize runs, add test/suppressions.txt file

In projects like property_map, the dynamic properties test explicitly
leaks memory.  We ignore this with a suppression file, and so can you.

.github/workflows/ci.yml

@@ -147,6 +147,9 @@ jobs:
             if [[ "${{ matrix.ccache }}" == "no" ]]; then
                 echo "B2_USE_CCACHE=0" >> $GITHUB_ENV
             fi
+            if [[ "${{ matrix.sanitize }}" == "yes" ]]; then
+                echo "LSAN_OPTIONS=suppressions=${GITHUB_WORKSPACE}/test/suppressions.txt" >> $GITHUB_ENV
+            fi
             git config --global pack.threads 0
             if [[ "${{matrix.container}}" == "ubuntu:1"* ]]; then
               # Node 20 doesn't work with Ubuntu 16/18  glibc: https://github.com/actions/checkout/issues/1590