analyzer: consider that realloc could shrink the buffer [PR106539]

analyzer: consider that realloc could shrink the buffer [PR106539]

This patch adds the "shrinks buffer" case to the success_with_move
modelling of realloc.

Regression-tested on Linux x86-64, further ran the analyzer tests with
the -m32 option.

2022-08-11  Tim Lange  <mail@tim-lange.me>

gcc/analyzer/ChangeLog:

	PR analyzer/106539
	* region-model-impl-calls.cc (region_model::impl_call_realloc):
	Use the result of get_copied_size as the size for the
	sized_regions in realloc.
	(success_with_move::get_copied_size): New function.

gcc/testsuite/ChangeLog:

	PR analyzer/106539
	* gcc.dg/analyzer/pr106539.c: New test.
	* gcc.dg/analyzer/realloc-5.c: New test.