Preserve stack-propagating-ness in fgSplitBlock
Preserve stack-propagating-ness in fgSplitBlock

If we're splitting a block that we've already marked as not propagating
stack (i.e. a point block), preserve that annotation on the newly-created
tail block (since it represents the same flow point as exit from the
original block).  The bit is left set on the original block (which becomes
the head); it's up to the caller to know why it's splitting the block here
and whether stack is propagated at this split point.

libengu/llilc,dotnet/llilc,tempbottle/llilc,marksantos/llilc,marksantos/llilc,dkorolev/llilc,pgavlin/llilc,mmitche/llilc,JosephTremoulet/llilc,swaroop-sridhar/llilc,kyulee1/llilcjit,russellhadley/llilc,swaroop-sridhar/llilc,JosephTremoulet/llilc,kyulee1/llilcjit,libengu/llilc,adiaaida/llilc,mmitche/llilc,dkorolev/llilc,richardlford/llilc,dkorolev/llilc,manu-silicon/llilc,AndyAyersMS/llilc,kyulee1/llilcjit,marksantos/llilc,JosephTremoulet/llilc,adiaaida/llilc,tempbottle/llilc,AndyAyersMS/llilc,richardlford/llilc,dotnet/llilc,dotnet/llilc,BruceForstall/llilc,libengu/llilc,adiaaida/llilc,AndyAyersMS/llilc,libengu/llilc,russellhadley/llilc,richardlford/llilc,russellhadley/llilc,pgavlin/llilc,BruceForstall/llilc,manu-silicon/llilc,manu-silicon/llilc,BruceForstall/llilc,swaroop-sridhar/llilc,tempbottle/llilc,pgavlin/llilc,mmitche/llilc,mmitche/llilc