gdbsupport: move fast_hash to gdbsupport/common-utils.h The following patch adds a hash type for gdb::string_view in gdbsupport, which will use the fast_hash function. Move the latter to gdbsupport. Change-Id: Id74510e17801e775bd5ffa5f443713d79adf14ad Approved-By: Andrew Burgess <aburgess@redhat.com>