Copy file1.txt to remote host in dw2-filename.exp and dw2-anonymous-func.exp

Copy file1.txt to remote host in dw2-filename.exp and dw2-anonymous-func.exp

Some gdb.dwarf2/*.exp tests copy file1.txt to host via gdb_remote_download
but dw2-filename.exp and dw2-anonymous-func.exp don't do that.  Looks like
an oversight in this patch
https://sourceware.org/ml/gdb-patches/2013-08/msg00365.html

There are some fails in remote host testing.
FAIL: gdb.dwarf2/dw2-anonymous-func.exp: list file1.txt
FAIL: gdb.dwarf2/dw2-filename.exp: interpreter-exec mi -file-list-exec-source-files
FAIL: gdb.dwarf2/dw2-filename.exp: info sources

This patch is to invoke gdb_remote_download to copy file1.txt to host
and remote it at the end.  This patch fixes these fails above.

gdb/testsuite:

2014-05-16  Yao Qi  <yao@codesourcery.com>

	* gdb.dwarf2/dw2-filename.exp: Copy file1.txt to host.  Remove
	file1.txt from host at the end.
	* gdb.dwarf2/dw2-anonymous-func.exp: Likewise.