tools: pass explicit section list to objdump
Objdump in recent versions of GNU binutils ignores bss sections unless they are specifically selected with the '-j' option. Symbols from these sections are needed for dtrace support. To fix this while retaining compatibility with previous versions of binutils, change to a two pass approach. The first pass extracts the list of unique sections, and the second pass invokes objdump with '-j' options for each of them.