[build-id] pass extended ids.txt to dump_breakpad_symbols

This change creates a concatenation of the ids.txt produced by the build
that that produced by the .build-id archives downloaded from CIPD - and
passes that to dump_breakpad_symbols.

Tested locally.

Bug: INTK-884 #comment
Bug: INTK-969 #comment
Change-Id: I9d96f8098239ca6a1c828be0a44dbe36a0c3b14a