[compiler-rt] Update libFuzzer build script to use C++17. (#89604)

libFuzzer uses std::clamp which was introduced in C++17.

GitOrigin-RevId: 791161516f48f41ae90f1231fdfc7374f43b5a9f
diff --git a/build.sh b/build.sh
index f7f329c..f58fd95 100755
--- a/build.sh
+++ b/build.sh
@@ -2,7 +2,7 @@
 LIBFUZZER_SRC_DIR=$(dirname $0)
 CXX="${CXX:-clang}"
 for f in $LIBFUZZER_SRC_DIR/*.cpp; do
-  $CXX -g -O2 -fno-omit-frame-pointer -std=c++14 $f -c &
+  $CXX -g -O2 -fno-omit-frame-pointer -std=c++17 $f -c &
 done
 wait
 rm -f libFuzzer.a