[analyzer][NFC] Add tests for extents

If we allocate memory, the extent of the MemRegion will be the symbolic
value of the size parameter. This way, if that symbol gets constrained,
the extent will be also constrained.

This test demonstrates that the extent is indeed the same symbol.

Reviewed By: NoQ

Differential Revision: https://reviews.llvm.org/D99959

GitOrigin-RevId: f0e102c1a39f0f7e9e309b27916533b8fefd9be7
1 file changed