gdb/python: Introduce gdb.lookup_static_symbols

gdb/python: Introduce gdb.lookup_static_symbols

If gdb.lookup_static_symbol is going to return a single symbol then it
makes sense (I think) for it to return a context sensitive choice of
symbol, that is the global static symbol that would be visible to the
program at that point.

However, if the user of the python API wants to instead get a
consistent set of global static symbols, no matter where they stop,
then they have to instead consider all global static symbols with a
given name - there could be many.  That is what this new API function
offers, it returns a list (possibly empty) of all global static
symbols matching a given name (and optionally a given symbol domain).

gdb/ChangeLog:

	* python/py-symbol.c (gdbpy_lookup_static_symbols): New
	function.
	* python/python-internal.h (gdbpy_lookup_static_symbols):
	Declare new function.
	* python/python.c (python_GdbMethods): Add
	gdb.lookup_static_symbols method.
	* NEWS: Mention gdb.lookup_static_symbols.

gdb/testsuite/ChangeLog:

	* gdb.python/py-symbol.exp: Add test for
	gdb.lookup_static_symbols.

gdb/doc/ChangeLog:

	* python.texi (Symbols In Python): Add documentation for
	gdb.lookup_static_symbols.

Change-Id: I1153b0ae5bcbc43b3dcf139043c7a48bf791e1a3