sarif-replay: fix off-by-one in handling of "endColumn" (§3.30.8) [PR118792]

sarif-replay: fix off-by-one in handling of "endColumn" (§3.30.8) [PR118792]

gcc/ChangeLog:
	PR sarif-replay/118792
	* libsarifreplay.cc (sarif_replayer::handle_region_object): Fix
	off-by-one in handling of endColumn property so that the code
	matches the comment and the SARIF spec (§3.30.8).

gcc/testsuite/ChangeLog:
	PR sarif-replay/118792
	* sarif-replay.dg/2.1.0-valid/error-with-note.sarif: Update
	expected output to reflect fix to off-by-one error in handling of
	"endColumn" property.
	* sarif-replay.dg/2.1.0-valid/malloc-vs-local-4.c.sarif: Likewise.
	* sarif-replay.dg/2.1.0-valid/signal-1.c.moved.sarif: Likewise.
	* sarif-replay.dg/2.1.0-valid/signal-1.c.sarif: Likewise.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>