BC: fixes for 5.18: special push_begin, fixed bytecode.pl
do not import B::amagic_generation, fix CC also >5.17

Fixed Conflicts:
	lib/B/C.pm
oops, amagic_generation CC
Changes CC amagic_generation
C: fixup wrong amagic_generation
Disassembler: aesthetics. move a case down
BC: fix 5.14-5.17, wrong defined(CvGV_set) logic

plus some ident changes
C: more PADLIST changes backported from master
C: quasi Config into XSLoader::load_file, special-case attributes

XSLoader::load_file does not load Config now.
attributes is since 5.011 dynaloaded, but added by the parser.
attributes::reftype still not correctly initialized.
remove dead code for internal XS functions, which are already booted.
force loading of attributes::bootstrap, without apparent success
C: Fixed HvAUX init. Previously only with magic hashes, now on all OOK hashes (OOK+SHAREKEYS)
C: skip AV->save_magic with PADLISTs
store lexical sub CvNAME_HEK (untested)

requires a patched B-1.44_01
CvNAME_HEK for lexsubs with patched B-1.4[24]_01

See RT#118525
5.19 updates: no BmRARE, BmPREVIOUS, new op_folded bit
C: fix syntax error elseif
better threads checks
fix PADLIST casts (still broken)
STATUS: 5.19.x status
fixup t/c_allow_opts.t 2x my