gprofng: Remove duplicate symbols

gprofng: Remove duplicate symbols

Remove all duplicate symbols which can be in SymLst.  The duplication
is due to processing of both static and dynamic symbols.  The
Stabs::removeDupSyms function is called before computing symbol
aliases.

Introduce a new vector function (i.e., truncate()), that truncates a
vector lenght to the given new count.  This functionis used by
removeDupSyms function.

Signed-off-by: Claudiu Zissulescu <claudiu.zissulescu-ianculescu@oracle.com>