Integrate changes #9544,9547,9549(perlio),9550,9551 from

Integrate changes #9544,9547,9549(perlio),9550,9551 from
maintperl into mainline.

"double" should be "NV"; standard typemap is missing entry
for NV

s/djSP/dSP/

Downgrade "Wide character in print" to a warning.

B::Deparse fix for ${^FOO} and documentation for PVX() method
(from Robin Houston)

tr/// doesn't null-terminate the result in some situations
(from Gisle Aas)

p4raw-link: @9549 on //depot/perlio: ae79846703a543a04b4fe449abfd6b1e08a9e149
p4raw-link: @9547 on //depot/maint-5.6/perl: 5976aebc9f997fdf4f4889f497e528a90c8a7dc3
p4raw-link: @9544 on //depot/maint-5.6/perl: 405f61b82790e3c0b3cb02962f34aa8522c5a18e

p4raw-id: //depot/perl@9553
p4raw-integrated: from //depot/maint-5.6/perl@9552 'copy in'
	ext/B/B/C.pm (@9235..) 'merge in' lib/ExtUtils/typemap
	(@8151..) ext/Thread/Thread.xs (@8606..) t/op/tr.t (@9152..)
	doop.c (@9288..) ext/B/B.pm ext/B/B/Deparse.pm (@9548..)
p4raw-integrated: from //depot/maint-5.6/perl@9544 'merge in'
	ext/B/B.xs (@8621..)