Optimize activity report SQL

We only log FLOW-LOG-SIGNATURE-METADATA from one place- FlowRunner. As a
result, we can swap the generalized regex for a prefix-only regex, saving a
<strong>lot</strong> of processing for our epp query (which is the most
expensive of the bunch).

I've also changed the test dates from 2017-05 to 2017-06, allowing us to copy-paste
the test data into Bigquery to verify their function. The reason for 2017-06 in particular is because June was the first month that populated all the metadata necessary to generate these reports.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=165391715

java/google/registry/reporting/ActivityReportingQueryBuilder.java

@@ -103,6 +103,10 @@ public final class ActivityReportingQueryBuilder {
             .put("PROJECT_ID", projectId)
             .put("ICANN_REPORTING_DATA_SET", ICANN_REPORTING_DATA_SET)
             .put("MONTHLY_LOGS_TABLE", getTableName(MONTHLY_LOGS))
+            // All metadata logs for reporting come from google.registry.flows.FlowReporter.
+            .put(
+                "METADATA_LOG_PREFIX",
+                "google.registry.flows.FlowReporter recordToLogs: FLOW-LOG-SIGNATURE-METADATA")
             .build();
     queriesBuilder.put(getTableName(EPP_METRICS), eppQuery);