gdb/testsuite: adjust test cases to previous "maintenance info line-table" change

gdb/testsuite: adjust test cases to previous "maintenance info line-table" change

Commit 904d9b02a185 ("gdb: make "maintenance info line-table" show
relocated addresses again") changed the format of that command, but
failed to adjust some test cases that relied on it.  This patch fixes
it.

The failures fixed are:

    FAIL: gdb.base/maint.exp: maint info line-table w/o a file name
    FAIL: gdb.dwarf2/dw2-out-of-range-end-of-seq.exp: END with address 1 eliminated
    FAIL: gdb.dwarf2/dw2-ranges-base.exp: count END markers in line table

Change-Id: I946580d5e100f1beeac99a9e90d7819c6bb4ac6c