Fixes bug where building JSC sometimes crashes at build-symbol-table-index.py. Also...

Fixes bug where building JSC sometimes crashes at build-symbol-table-index.py. Also adds licenses.
https://bugs.webkit.org/show_bug.cgi?id=133814

Reviewed by Filip Pizlo.

Adds the "shopt -s nullglob" line necessary to prevent the loop in the shell
script from using "*.o" as a file when no other files in the directory exist.

* build-symbol-table-index.sh: Added license.
* copy-llvm-ir-to-derived-sources.sh: Added license and "shopt -s nullglob" line.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@170076 268f45cc-cd09-0410-ab3c-d52691b4dbfc