Fix copy-more-arg on ARM.
Improve testing for subtypes of 1-dimensional simple-arrays

This needs some additional work for platforms other than x86[-64].

Also sprinkle around some meta-comments about obsolete comments.
Addendum to previous change which added SIMPLE-RANK-1-ARRAY-*-P
One more omission from widetag tests. Third time's the charm?
Adjust control-stack size on ARM.

Now that copy-more-arg is fixed, it can be reduced, set size to 2 and
size-increment to 1.
More immediate encoding fixes on ARM.

This time dealing with large stack frames.
Update sb-gmp fixing mpz_remove.
Add disassemble for BX and BLX on ARM.
Add --load parameter for make-target-2.sh, skipping compilation.
Better warning for SB-ALIEN:SLOT on missing slots.

The previous one was
"#<SB-C::LVAR 1 {100B1FC043}> doesn't have a slot named NAME".
Implement alien-callbacks on ARM.
Liberalize the assertion for widetag range compression test
Recognize SYMBOL-HEADER-WIDETAG in WIDETAGS-FROM-UNION-TYPE

This change improves (TYPEP x 'SB-KERNEL:STRING-DESIGNATOR)
Mostly implement %OTHER-POINTER-SUBTYPE-P for PPC

It lacks the :exclude feature as on x86[-64] but works fine without
Update sb-gmp and sb-mpfr.

This fixes issues with mpz-remove tests failing.
Liberalize another assertion for widetag range compression test

The previous fix in commit 98c61848748078bd412af0f03ade50dcf85170eb
missed the

  (or system-area-pointer (sb-kernel:simple-unboxed-array (*)))

case which was failing for sb-safepoint builds as well.
Add SB-THREAD:INTERACTIVE-THREADS

Also have SB-THREAD:FOREGROUND-THREAD accept the session as an optional
parameter.
Document INTERACTIVE-THREADS, FOREGROUND-THREAD
SAVE-LISP-AND-DIE signals SAVE-WITH-MULTIPLE-THREADS-ERROR

The report of the new condition class SAVE-WITH-MULTIPLE-THREADS-ERROR
contains the interactive threads of the current session and all other
threads to make analyzing the problem easier.

Also define superclass conditions SAVE-{CONDITION,ERROR}.
Undo the change that added a %FUN-POINTER-WIDETAG reader.

It's just FUN-SUBTYPE, though questionable why SAP-REF-8
is getting re-implemented anew by each backend.