Check return values of some internal arithmetic operations.

This was hunting for the message below. I don't think the extra checks
are in the right place. We basically must find a success path for is/2
after check_float() returns FALSE.

Foreign predicate system:is/2 did not clear exception:
error(evaluation_error(float_overflow),context(system: (is)/2,_G3441))
scan_options(): reclaim term-references if possible.
FIXED: thread_get_message/1,2: avoid leaking term-references if waiting
is repeatedly interrupted.  This might be an important reason for crashes
in long running servers.  It surely is a bug.
FIXED: Throw error on retractall(3).  Paulo Moura.
FIXED: retractall/1 on reserved (ISO) predicates.  Paulo Moura.
CLEANUP: Avoid -fsanitize runtime error in MPZ-->int64 translation (not
really an error).  Abramo Bagnara.
ENHANCED: group_pairs_by_key/2 now also works for variable keys.
FIXED: propagate errors from promoteToFloatNumber().  Before, some
arithmetic operations that imply conversion to floats of rationals
(including integers) that are outside the IEEE double float range
could give an incorrect result.
"is is" ==> "is"
FIXED: library(sandbox) handling of findall/4.
MODIFIED: predicate_property(++P, visible) now also succeeds for `hidden'
$-predicates.  Hidden predicates are skipped when generating visible
predicates.
ADDED: library(sandbox) declaration for findnsols/4,5.
Preparing version 7.1.25
Updated sgml
Updated sgml
FIXED: setup_call_cleanup/4: Avoid superfluous calling of the cleanup
handler because FR_WATCHED is set by the debugger or frame inspection.
Matt Lilley.
Avoid runtime lookup of user:event_hook/1.
Cleanup calling of (debugger) event hook.  Avoid a function call for the
common case that the hook is not installed and centralise dependency on
whether or not the debugger is configured.