Improve diagnostic output for trace2 data assertions #28736

Job	Run time
config	8s
fuzz smoke test	1m 36s
win build	5m 1s
documentation	7m 13s
rust-analysis	1m 32s
win+Meson build	4m 14s
static-analysis	5m 31s
sparse	3m 45s
osx-clang (macos-14)	6h 0m 17s
osx-reftable (macos-14)	38m 42s
osx-meson (macos-14)	1h 8m 33s
osx-gcc (macos-14)	6h 0m 17s
almalinux-8 (almalinux:8)	14m 32s
linux-reftable (ubuntu:rolling)	28m 26s
linux-meson (ubuntu:rolling)	25m 51s
fedora-breaking-changes-meson (fedora:latest)	18m 12s
linux-musl-meson (alpine:latest)	23m 38s
linux-leaks (ubuntu:rolling)	49m 50s
linux-breaking-changes (ubuntu:rolling)	24m 39s
debian-11 (debian:11)	25m 27s
linux-sha256 (ubuntu:rolling)	22m 38s
linux-TEST-vars (ubuntu:20.04)	24m 23s
linux32 (i386/ubuntu:20.04)	6h 0m 5s
linux-asan-ubsan (ubuntu:rolling)	1h 11m 51s
linux-reftable-leaks (ubuntu:rolling)	46m 56s
win+VS build	-1s
win+VS test	-1s
win+Meson test (4)	39m 12s
win+Meson test (9)	6m 59s
win+Meson test (7)	6m 34s
win+Meson test (6)	13m 3s
win+Meson test (1)	7m 27s
win+Meson test (2)	45m 49s
win+Meson test (3)	11m 44s
win+Meson test (8)	9m 59s
win+Meson test (5)	9m 2s
win+Meson test (0)	8m 8s
win test (4)	46m 35s
win test (5)	9m 56s
win test (2)	7m 28s
win test (1)	7m 57s
win test (0)	10m 1s
win test (9)	6m 4s
win test (3)	11m 55s
win test (7)	7m 31s
win test (8)	5m 11s
win test (6)	34m 7s
	1d 7h 37m 57s

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