PR 17564: Fix objfile search order for static symbols.

PR 17564: Fix objfile search order for static symbols.

When searching static symbols, gdb would search over all
expanded symtabs of all objfiles, and if that fails only then
would it search all partial/gdb_index tables of all objfiles.
This means that the user could get a random instance of the
symbol depending on what symtabs have been previously expanded.
Now the search is consistent, searching each objfile completely
before proceeding to the next one.

gdb/ChangeLog:

	PR symtab/17564
	* symtab.c (lookup_symbol_in_all_objfiles): Delete.
	(lookup_static_symbol): Move definition to new location and rewrite.
	(lookup_symbol_in_objfile): New function.
	(lookup_symbol_global_iterator_cb): Call it.

gdb/testsuite/ChangeLog:

	PR symtab/17564
	* gdb.base/symtab-search-order.exp: New file.
	* gdb.base/symtab-search-order.c: New file.
	* gdb.base/symtab-search-order-1.c: New file.
	* gdb.base/symtab-search-order-shlib-1.c: New file.