Change in coreboot[master]: tests: Add lib/stack-test test case

[Name of user not set (Code Review)]

Attention is currently required from: Martin Roth, Paul Fagerburg, Jan Dabros.
[e-mail] has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/50305 )

Change subject: tests: Add lib/stack-test test case
......................................................................

Patch Set 4:

(1 comment)

File tests/lib/stack-test.c:

https://review.coreboot.org/c/coreboot/+/50305/comment/fc92ad97_25b841a5 
PS1, Line 102: 		stack[i] = 0x42420707;
> I agree, the stack is almost always an even number of machine words, often a power of 2. […]

Ok, I changed it back to previous form. Thank you :)