Revert "Reject jumping inside stmtexprs"
Revert "Reject jumping inside stmtexprs"

Not fully thought out.  You can't jump inside stmt exprs,
but you can jump out of them.  So there's a difference
between undefined but declared labels at the end of stmt
exprs and those defined inside.  Additionally it should
also be checked if a label defined inside a stmt expr
was tentatively created as declared from outside.

I'm not prepared doing that right now, so simply revert.

This reverts commit 9160e4cab9147d77840cc44a285031fdb4640cf9.

run4flat/tinycc,mingodad/tinycc,mingodad/tinycc,code4game/tinycc,run4flat/tinycc,code4game/tinycc,avih/tinycc,mirror/tinycc,mingodad/tinycc,avih/tinycc,andreiw/tinycc,mirror/tinycc,run4flat/tinycc,avih/tinycc,andreiw/tinycc,mirror/tinycc,andreiw/tinycc,avih/tinycc,mingodad/tinycc,run4flat/tinycc,run4flat/tinycc,mirror/tinycc,code4game/tinycc