GC: Clarify debug output to avoid misleading allocation counts
The GC debug status output previously displayed "Allocations: X" which
misleadingly suggested an exact count of allocations. In reality, these
counters (poolalloc and bigalloc) may not accurately reflect the total
number of allocations, especially in short-lived processes or during
fatal errors when thread-local counts haven't been combined.
Changed the output format from:
"Allocations: 1 (Pool: 1; Big: 0); GC: 0"
to:
"GC tracked (pool: 1, big: 0); GC pauses: 0"
This makes it clear that these are tracked counts (which may be incomplete)
rather than claiming to be an accurate total allocation count. Also renamed
"GC: X" to "GC pauses: X" for clarity.
Fixes #60125
