Integrate changes #10450 and #10451 from maintperl:

Integrate changes #10450 and #10451 from maintperl:

optimize change#10448 slightly (don't repeat search in eval""s lexical
scope, since that has already been searched)

change#9108 needs subtler treatment for case of closures created
within eval""

p4raw-link: @10450 on //depot/maint-5.6/perl: 77991f234c231cb11047bb180fdeef1134557583
p4raw-link: @10448 on //depot/maint-5.6/perl: 332ba4f98bc63c81fd7ba0d06432a7f903d716cf
p4raw-link: @9108 on //depot/maint-5.6/perl: 1cf1f64f42eb50a67f2427ff9d6d24023a2b9997

p4raw-id: //depot/perl@10454
p4raw-integrated: from //depot/maint-5.6/perl@10453 'merge in'
	t/op/misc.t (@10448..) op.c (@10450..)