Tweak gdbserver_tests/hgtls.stdoutB.exp filter_gdb a little for older GDB.

Older GDB (7.2 on i386) don't print out which variable+offset an argument
pointer in a breakpoint function points to. The hgtls test already tests
whether the p pointer/test points to the expected tests array element.
So don't expect gdb to print it also and filter it out with filter_gdb.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14331 a5019735-40e9-0310-863c-91ae7b9d1cf9