Enable shared library list population in Gecko Profiler

[dmik]

This is a continuation of #264. So far, SharedLibraryInfo::GetInfoForSelf() (tools/profiler/core/shared-libraries-os2.cc) returns an empty list. When we really need the profiler, we may want to use DosQuerySysState(QS_MTE) to walk the process DLLs and populate the list.

[dmik]

Note that in order to actually use the profiler, one should build Mozilla with --enable-profiling.