pgAdmin 4 commit: Add support for pre-condition SQL in RE-SQL testsuite

Add support for pre-condition SQL in RE-SQL testsuite,
and use it to ensure that the right extensions are installed for the
extension tests.

Branch
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electron2

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=8c41296d2dbe4133c42e96538606e5a2100e1613
Author: Nagesh Dhope <nagesh.dhope@enterprisedb.com>

Modified Files
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.../databases/extensions/tests/9.4_plus/tests.json | 18 ++++++++++------
.../databases/extensions/tests/9.5_plus/tests.json |  9 +++++---
.../databases/extensions/tests/9.6_plus/tests.json | 18 ++++++++++------
web/regression/re_sql/tests/test_resql.py          | 25 ++++++++++++++++++++++
4 files changed, 55 insertions(+), 15 deletions(-)