The LIT test cases were migrated with the script provided by
Nikita Popov.
No manual changes were made. Committed without review since
no functional changes, after consultation with uweigand.
When a function does a dynamic stack allocation, the function's stack
size (in the stack map) is reported as UINT64_MAX.
This change tests and documents this property.
Differential Revision: https://reviews.llvm.org/D128525