fuzz-introspector: force use of llvm-nm instead of nm (#7533)

This fixes various current build failures across projects that use nm as
part of their build process.

infra/base-images/base-builder/compile

@@ -149,13 +149,16 @@ fi
 if [ "$SANITIZER" = "introspector" ]; then
   export LDFLAGS="-fuse-ld=gold -flto"
   export AR=llvm-ar
+  export NM=llvm-nm
   export RANLIB=llvm-ranlib
 
   # Move ar and ranlib
   mv /usr/bin/ar /usr/bin/old-ar
+  mv /usr/bin/nm /usr/bin/old-nm
   mv /usr/bin/ranlib /usr/bin/old-ranlib
 
   ln -sf /usr/local/bin/llvm-ar /usr/bin/ar
+  ln -sf /usr/local/bin/llvm-nm /usr/bin/nm
   ln -sf /usr/local/bin/llvm-ranlib /usr/bin/ranlib
 fi
 

infra/base-images/base-clang/checkout_build_install_llvm.sh

@@ -225,6 +225,7 @@ mv \
   /usr/local/bin/llvm-config \
   /usr/local/bin/llvm-cov \
   /usr/local/bin/llvm-objcopy \
+  /usr/local/bin/llvm-nm \
   /usr/local/bin/llvm-profdata \
   /usr/local/bin/llvm-ranlib \
   /usr/local/bin/llvm-symbolizer \