Add wall clock timestamp for ConfigMetricsReport and gauge atoms.

Fix the bug when serializing multiple atoms in gauge metric

BUG: b/74159560

Test: new test for ALL_CONDITION_CHANGES sampling method.
Change-Id: I6d33c1efbac92b6e13be2d64c323e090cb1f84aa
diff --git a/cmds/statsd/Android.mk b/cmds/statsd/Android.mk
index 7f0a26c..1418065 100644
--- a/cmds/statsd/Android.mk
+++ b/cmds/statsd/Android.mk
@@ -198,7 +198,7 @@
     tests/e2e/WakelockDuration_e2e_test.cpp \
     tests/e2e/MetricConditionLink_e2e_test.cpp \
     tests/e2e/Attribution_e2e_test.cpp \
-    tests/e2e/GaugeMetric_e2e_test.cpp \
+    tests/e2e/GaugeMetric_e2e_push_test.cpp \
     tests/e2e/DimensionInCondition_e2e_combination_AND_cond_test.cpp \
     tests/e2e/DimensionInCondition_e2e_combination_OR_cond_test.cpp \
     tests/e2e/DimensionInCondition_e2e_simple_cond_test.cpp