Describe the bug
java.sql.SQLRecoverableException: Closed Connection
This seems to happen after 4 hours.

Provide version info
Database version 12.2.0.1.0
UT Version v3.1.10.3349

Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production
PL/SQL Release 12.2.0.1.0 - Production
"CORE 12.2.0.1.0 Production"
TNS for Linux: Version 12.2.0.1.0 - Production
NLSRTL Version 12.2.0.1.0 - Production

NLS_LANGUAGE AMERICAN
NLS_TERRITORY IRELAND
NLS_CURRENCY €
NLS_ISO_CURRENCY IRELAND
NLS_NUMERIC_CHARACTERS .,
NLS_CALENDAR GREGORIAN
NLS_DATE_FORMAT DD-MON-RR
NLS_DATE_LANGUAGE AMERICAN
NLS_SORT BINARY
NLS_TIME_FORMAT HH12:MI:SSXFF AM
NLS_TIMESTAMP_FORMAT DD-MON-RR HH24:MI:SSXFF
NLS_TIME_TZ_FORMAT HH12:MI:SSXFF AM TZR
NLS_TIMESTAMP_TZ_FORMAT DD-MON-RR HH24:MI:SSXFF TZR
NLS_DUAL_CURRENCY €
NLS_COMP BINARY
NLS_LENGTH_SEMANTICS CHAR
NLS_NCHAR_CONV_EXCP FALSE

x86_64/Linux 2.4.xx

Information about client software
utplsql cli
utPLSQL-cli 3.1.8-SNAPSHOT.local
utPLSQL-java-api 3.1.8.546

To Reproduce
Run the following.
./utplsql run username/password@database:1521/utplsqltestdb -s -t 780 -f=ut_coverage_html_reporter -o=coverage.html

Expected behavior
Expect the reports to be produced.

Additional context
Our database is fairly large, 4.9 million relevant lines.
If I pass a -p parameter to keep it to one subset of tests it runs (approx 3 hours) and generates the coverage report.
However I need a complete report so removed the -P
Seems to always time out after 4 hours.
Running locally on the db server (to avoid any network/firewall timeout) shows the same result.
Nothing in the Oracle alert log/tracefiles, in fact the sql is still running in the database after the disconnect indicating a timeout on the client.