Move psymbol_map out of objfile

Move psymbol_map out of objfile

objfile::psymbol_map is used to implement a Rust feature.  It is
currently specific to partial symbols -- it isn't used by the DWARF
indices.

This patch moves it out of objfile and into psymbol_functions, adding
a new method to quick_symbol_functions to handle the clearing case.
This is needed because the map holds unrelocated addresses.

gdb/ChangeLog
2021-03-20  Tom Tromey  <tom@tromey.com>

	* quick-symbol.h (struct quick_symbol_functions)
	<relocated>: New method.
	* psymtab.h (struct psymbol_functions) <relocated>: New
	method.
	<fill_psymbol_map>: Declare method.
	<m_psymbol_map>: New member.
	* psymtab.c (psymbol_functions::fill_psymbol_map): Rename.
	(psymbol_functions::find_compunit_symtab_by_address): Update.
	* objfiles.h (reset_psymtabs): Don't clear psymbol_map.
	(struct objfile) <psymbol_map>: Remove.
	* objfiles.c (objfile_relocate1): Update.