Fix end_sequence addresses for dw2-lines.exp

Fix end_sequence addresses for dw2-lines.exp

The patch:

  From f0d556d14b1d1c3f8e2f9c13b08adca22e1b8c9c Mon Sep 17 00:00:00 2001
  From: Tom de Vries <tdevries@suse.de>
  Date: Wed, 17 Apr 2024 12:55:00 +0200
  Subject: [PATCH] [gdb/testsuite] Fix end_sequence addresses

  I noticed in test-case gdb.reverse/map-to-same-line.exp, that the end of main:
  ...
  00000000004102c4 <end_of_sequence>:
    4102c4:       52800000        mov     w0, #0x0                        // #0
   4102c8:       9100c3ff        add     sp, sp, #0x30
    4102cc:       d65f03c0        ret
  ...
  is not described by the line table:
  ...

  <snip>

The regression failure on PowerPC is due to the change in file
dw2-lines.exp,

-               DW_LNE_set_address bar_label_5
+               DW_LNE_set_address "$main_start + $main_len"

The label bar_label_5 is in function bar, not function main.  The new
set address should have been $bar_start + $bar_len.