fix up cleanup handling in internal_vproblem

internal_vproblem can return, so this introduces proper cleanup
handling there.  Otherwise it may make a cleanup that is leaked.

	* utils.c (internal_vproblem): Call do_cleanups.
cleanup fixes for remote-mips.c

remote-mips.c has a few 'return's where cleanups are not run.

	* remote-mips.c (mips_exit_debug): Call do_cleanups on all
	return paths.
	(mips_initialize): Likewise.
	(common_open): Call do_cleanups.
cleanup fixes for inf-ptrace.c

This is one of the stylistic patches.  The code here in inf-ptrace.c
is not incorrect, but it is in a style that the cleanup checker cannot
handle.  This patch changes it to a simpler style, following the usual
method of introducing an unconditional "outer" cleanup.

	* inf-ptrace.c (inf_ptrace_create_inferior): Unconditionally
	call discard_cleanups.
	(inf_ptrace_attach): Likewise.
fix list_available_thread_groups

list_available_thread_groups, in mi-main.c, leaks a cleanup.
This changes it to call do_cleanups.

	* mi/mi-main.c (list_available_thread_groups): Call do_cleanups.
fix cleanup handling in m32r_load

m32r_load is missing a call to do_cleanups along one return path.

	* m32r-rom.c (m32r_load): Call do_cleanups at all returns.
fix cleanup handling in macho_symfile_read

macho_symfile_read leaks a cleanup by assigning to 'back_to' too late.

	* machoread.c (macho_symfile_read): Assign first cleanup to
	'back_to'.
fix two buglets in breakpoint.c

First, output_thread_groups leaks a cleanup along one return path.

Second, parse_cmd_to_aexpr could return without running its cleanups,
if there was an exception in a TRY_CATCH.

	* breakpoint.c (output_thread_groups, parse_cmd_to_aexpr): Call
	do_cleanups earlier.
make a cleanup unconditionally in tracepoint.c

This is another cosmetic patch.  It introduces an "outer" cleanup in
trace_dump_command and arranges to unconditionally call do_cleanups.
This lets the checker analyze the function.

	* tracepoint.c (trace_dump_command): Unconditionally call
	do_cleanups.
fix varobj.c

c_value_of_root is missing a call to do_cleanups at one return.
This fixes the problem by removing that return and letting control
fall through.

	* varobj.c (c_value_of_root): Call do_cleanups along all
	return paths.
simplify cli-logging.c for analysis

This is another stylistic patch.  It changes cli-logging.c to be
analyzable by the checker, again following the method of adding an
outer cleanup and unconditionally calling do_cleanups.

	* cli/cli-logging.c (set_logging_redirect): Unconditionally
	call do_cleanups.
fix py-breakpoint.c

One return path in bppy_get_commands was missing a do_cleanups call.

	* python/py-breakpoint.c (bppy_get_commands): Call do_cleanups
	along all return paths.
fix py-frame.c

A couple return paths in frapy_read_var were missing do_cleanups calls.

	* python/py-frame.c (frapy_read_var): Call do_cleanups along
	all return paths.
fix py-prettyprint.c

print_children, in py-prettyprint.c, could call do_cleanups twice on
the same cleanup.

	* python/py-prettyprint.c (print_children): Remove extra
	do_cleanups call.
fix py-value.c

Some code in py-value.c could exit a loop without running some
cleanups made in the loop.

	* python/py-value.c (valpy_binop): Call do_cleanups before
	exiting loop.
fix symtab.c

search_symbols had some bad code resulting in a cleanup being both
discarded and run.

	* symtab.c (search_symbols): Introduce a null cleanup for
	'retval_chain'.
fix one bug in symfile.c

find_separate_debug_file could leak a cleanup along some return paths.

	* symfile.c (find_separate_debug_file): Call do_cleanups
	along all return paths.
fix mipsread.c

Some code in mipsread.c could leak cleanups along some return paths.

	* mipsread.c (read_alphacoff_dynamic_symtab): Call do_cleanups
	along all return paths.
	* mips-linux-tdep.c: Adjust formatting throughout.
fix one bug in stabsread.c

Some code in stabsread.c can return without running cleanups.

	* stabsread.c (read_struct_type): Call do_cleanups along
	all return paths.
fix top.c

execute_command can leak a cleanup along one return path.

	* top.c (execute_command): Discard 'cleanup_if_error' cleanups.