[NFC] firefox: Fix build for new solbuild

packages/f/firefox/package.yml

@@ -87,6 +87,7 @@ build      : |
         # Package and run automated benchmarks for profiling
         # Use software rendering (LIBGL_ALWAYS_SOFTWARE=true) everywhere to work around potential display issues
         ./mach package
+        HOME=/root \
         JARLOG_FILE="$PWD/jarlog" \
         LLVM_PROFDATA=llvm-profdata \
         LIBGL_ALWAYS_SOFTWARE=true \
@@ -95,6 +96,8 @@ build      : |
           xvfb-run -s "-screen 0 1920x1080x24 -nolisten local" \
             ./mach python build/pgo/profileserver.py
 
+        export HOME=/home/build
+
         stat -c "Profile data found (%s bytes)" merged.profdata
         test -s merged.profdata