Add testcase for PR57478


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@199531 138bc75d-0d04-0410-961f-82ee72b054a4
Fix gcc.dg/shrink-wrap-alloca.c

	* gcc.dg/shrink-wrap-alloca.c: Use __builtin_alloca.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@199533 138bc75d-0d04-0410-961f-82ee72b054a4