Add stack canaries / strcpy tests.

Add a test to ensure that stack canaries are working
correctly. Since stack canaries aren't normally generated
on non-string functions, we have to enable stack-protector-all.

Add a test to ensure that an out of bounds strcpy generates
a runtime failure.

Change-Id: Id0d3e59fc4b9602da019e4d35c5c653e1a57fae4