Skip directory tests in gdb.base/info_sources.exp on remote host

Skip directory tests in gdb.base/info_sources.exp on remote host

When testing on a remote host, source files from build are copied to
an arbitrary location on host.  Tests that try to pattern-match host
pathnames against directory prefixes on build don't generally work.

2020-07-13  Sandra Loosemore  <sandra@codesourcery.com>

	gdb/testsuite/
	* gdb.base/info_sources.exp: Skip directory match tests on
	remote hosts.