Use RUN_TEST and fix installed krb5.conf uses

Use RUN_TEST and fix installed krb5.conf uses

Use $(RUN_TEST) to run most C test programs, for simplicity and to fix
accidental uses of the installed krb5.conf.  Where a particular
krb5.conf must be used instead of the one in src/config-files, use a
locally defined variant like RUN_TEST_LOCAL_CONF.

Accidental references to the installed krb5.conf were present when
running t_pac, t_princ, t_etypes, t_trace, t_attr, t_attrset,
t_packet, t_remote, t_client, pkinit_kdf_test, test_chpw_message,
text_cxx_krb5, and test_cxx_k5int.

Based on a patch from Robbie Harwood.

ticket: 8266
target_version: 1.14
tags: pullup