Add missing common mathematical function (absolute value)

[dalg24]

Partially addressing #4033

[masterleinad]

I have a slight preference towards something like

diff --git a/.github/workflows/continuous-integration-workflow.yml b/.github/workflows/continuous-integration-workflow.yml
index 892ca127a..c2ce93235 100644
--- a/.github/workflows/continuous-integration-workflow.yml
+++ b/.github/workflows/continuous-integration-workflow.yml
@@ -45,6 +45,13 @@ jobs:
       - name: maybe_disable_death_tests
         if: ${{ matrix.distro == 'fedora:rawhide' }}
         run: echo "GTEST_FILTER=-*DeathTest*" >> $GITHUB_ENV
+      - name: enable_precise_fp_mode
+        run: |
+          if ${{ matrix.cxx == 'icpx' }}; then
+            echo "EXTRA_CXX_FLAGS=-fp-model=precise" >> $GITHUB_ENV
+          else
+            echo "EXTRA_CXX_FLAGS=" >> $GITHUB_ENV
+          fi
       - name: build-and-test
         run: |
           ccache -z
@@ -56,6 +63,7 @@ jobs:
             -DKokkos_ENABLE_EXAMPLES=ON \
             -DKokkos_ENABLE_DEPRECATED_CODE_3=ON \
             -DCMAKE_CXX_COMPILER=${{ matrix.cxx }} \
+            -DCMAKE_CXX_FLAGS=${EXTRA_CXX_FLAGS} \
             -DCMAKE_BUILD_TYPE=${{ matrix.cmake_build_type }} \
             -DBUILD_NAME=${{ matrix.distro }}-${{ matrix.cxx }} \
             -DBUILD_JOBS=2 -DBINARY_DIR=builddir -DSITE=GitHub-Linux \

see https://github.com/masterleinad/kokkos/runs/2640376010?check_suite_focus=true saying "We only test in floating point safe mode. You are on your own if you use unsafe floating point operations (that happen to be enabled by default in certain Intel compilers)."
I can live with either, though.

[masterleinad]

Retest this please.

[masterleinad]

Retest this please.