docs: switch CMC upgrade test results to single UTC-based cumulative file

tests/cmc-upgrade-test.md

@@ -97,10 +97,10 @@ Validate CMC behavior across staged kernel upgrades on a cloned VM, including re
 - Any critical migration/service validation failure that blocks continuation.
 
 ## Per-Host Test Result Record
-Create one report per tested host.
+Use one cumulative results file and append one new section per tested host.
 
 ### Host Metadata
-- Test date/time:
+- Test date/time (UTC):
 - Operator:
 - Source VM:
 - Cloned VM name:
@@ -139,6 +139,10 @@ Create one report per tested host.
 - Blocking issue summary:
 - Follow-up actions:
 
+## Timestamp Standard
+- All recorded test timestamps must use UTC.
+- Format: `YYYY-MM-DD HH:MM UTC`
+
 ## Result Storage Location
-Store per-host test results under:
-- `/home/aw/code/cds/tmp/tests/cmc upgrade test/`
+Store and append all per-host results in:
+- `/home/aw/code/cds/tmp/tests/cmc upgrade test/cmc-upgrade-kernel-test-results.md`