trace2: tolerate failed timestamp formatting #29050

Job	Run time
config	7s
fuzz smoke test	2m 1s
win+Meson build	4m 17s
win build	3m 38s
win+VS build	-1s
static-analysis	5m 5s
documentation	7m 31s
rust-analysis	1m 51s
sparse	3m 41s
osx-gcc (macos-14)	35m 29s
osx-clang (macos-14)	36m 21s
osx-meson (macos-14)	43m 16s
osx-reftable (macos-14)	32m 38s
linux32 (i386/ubuntu:20.04)	6h 0m 5s
linux-leaks (ubuntu:rolling)	36m 57s
linux-TEST-vars (ubuntu:20.04)	23m 10s
linux-asan-ubsan (ubuntu:rolling)	45m 7s
linux-reftable (ubuntu:rolling)	16m 37s
linux-meson (ubuntu:rolling)	23m 43s
linux-sha256 (ubuntu:rolling)	16m 15s
linux-musl-meson (alpine:latest)	6h 5m 0s
linux-breaking-changes (ubuntu:rolling)	28m 25s
almalinux-8 (almalinux:8)	21m 16s
fedora-breaking-changes-meson (fedora:latest)	16m 32s
linux-reftable-leaks (ubuntu:rolling)	46m 33s
debian-11 (debian:11)	21m 13s
win+VS test	0s
win test (1)	7m 28s
win test (2)	5m 16s
win test (3)	10m 46s
win test (6)	59m 59s
win test (5)	7m 59s
win test (9)	7m 49s
win test (7)	5m 32s
win test (4)	10m 16s
win test (8)	25m 10s
win test (0)	7m 31s
win+Meson test (6)	30m 4s
win+Meson test (8)	8m 18s
win+Meson test (2)	8m 31s
win+Meson test (7)	10m 31s
win+Meson test (5)	11m 25s
win+Meson test (4)	9m 0s
win+Meson test (0)	9m 32s
win+Meson test (9)	8m 38s
win+Meson test (3)	58m 24s
win+Meson test (1)	6m 19s
	1d 1h 5m 15s

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