Actually expand the %t1 patterns (in RUN: lines) to a unique

filename.
This fixes (e.g.) CodeGen/struct-x86-darwin.c which
raced at writing to "%t1" with other tests when parallel
testing was specified with a high "-j XX" value.

Also gets rid of the file tools/clang/test/%t1
when doing an "svn st" after testing.

llvm-svn: 48454