avoid exits from MMG5_coltet() #569

Job	Run time
mmg-debug / ci (ubuntu-20.04, on, off, on, off, int32_t)	1h 19m 28s
mmg-debug / ci (ubuntu-20.04, on, off, off, off, int32_t)	1h 38m 36s
mmg-debug / ci (ubuntu-20.04, off, off, on, off, int32_t)	1h 2m 40s
mmg-debug / ci (ubuntu-20.04, off, off, off, off, int32_t)	1h 11m 16s
mmg-debug / ci (macos-12, on, off, on, off, int32_t)	41m 13s
mmg-debug / ci (macos-12, on, off, off, off, int32_t)	1h 8m 14s
mmg-debug / ci (macos-12, off, off, on, off, int32_t)	35m 2s
mmg-debug / ci (macos-12, off, off, off, off, int32_t)	40m 1s
mmg-debug / ci (ubuntu-20.04, off, off, off, on, int32_t)	3m 38s
mmg-debug / ci (macos-12, off, off, off, on, int32_t)	8m 27s
mmg-debug / ci (ubuntu-20.04, off, on, on, off, int32_t)	1h 1m 57s
mmg-debug / ci (macos-12, off, on, on, off, int32_t)	32m 48s
mmg-debug / ci (windows-2022, off, off, off, off, int32_t)	53m 40s
mmg-debug / ci (windows-2022, on, off, off, off, int32_t)	53m 39s
mmg-debug / ci (windows-2022, off, on, off, off, int32_t)	57m 27s
mmg-debug / ci (ubuntu-20.04, on, on, on, on, int64_t)	4m 42s
mmg-debug / ci (ubuntu-20.04, off, off, on, on, int64_t)	1h 11m 23s
mmg-debug / ci (ubuntu-20.04, off, off, off, off, int64_t)	1m 44s
mmg-debug / ci (macos-12, on, on, on, on, int64_t)	7m 14s
mmg-debug / ci (macos-12, off, off, off, off, int64_t)	5m 1s
mmg-debug / ci (windows-2022, on, on, off, off, int64_t)	4m 5s
mmg-debug / ci (windows-2022, off, off, off, off, int64_t)	4m 44s
	14h 26m 59s

Provide feedback