Use gcc for coverage build

It's probably too noisy and I don't even look anyway

Jenkinsfile

@@ -13,8 +13,6 @@ def CleanBuildAndTest(String cmakeArgs) {
         cd build
         ctest --no-compress-output --test-output-size-passed 100000 --test-output-size-failed 100000 -T Test -j `nproc` --timeout 90
         zstd Testing/*/Test.xml
-        LD_LIBRARY_PATH=skip_list ./conflict_set_bench
-        LD_LIBRARY_PATH=radix_tree ./conflict_set_bench
         '''
     }
     xunit tools: [CTest(pattern: 'build/Testing/*/Test.xml')], reduceLog: false, skipPublishingChecks: false
@@ -85,9 +83,9 @@ pipeline {
                 }
             }
             steps {
-                CleanBuildAndTest("-DCMAKE_C_FLAGS=--coverage -DCMAKE_CXX_FLAGS=--coverage -DCMAKE_BUILD_TYPE=Debug")
+                CleanBuildAndTest("-DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ -DCMAKE_C_FLAGS=--coverage -DCMAKE_CXX_FLAGS=--coverage -DCMAKE_BUILD_TYPE=Debug")
                 sh '''
-                gcovr --gcov-executable "llvm-cov-15 gcov" --exclude '.*third_party.*' --cobertura > build/coverage.xml
+                gcovr --exclude '.*third_party.*' --cobertura > build/coverage.xml
                 '''
                 cobertura autoUpdateHealth: false, autoUpdateStability: false, coberturaReportFile: 'build/coverage.xml', conditionalCoverageTargets: '70, 0, 0', failUnhealthy: false, failUnstable: false, lineCoverageTargets: '80, 0, 0', maxNumberOfBuilds: 0, methodCoverageTargets: '80, 0, 0', onlyStable: false, sourceEncoding: 'ASCII', zoomCoverageChart: false
             }