test: add is_bdb_compiled helper

test/config.ini.in

@@ -17,6 +17,7 @@ RPCAUTH=@abs_top_srcdir@/share/rpcauth/rpcauth.py
 # Which components are enabled. These are commented out by `configure` if they were disabled when running config.
 @ENABLE_WALLET_TRUE@ENABLE_WALLET=true
 @USE_SQLITE_TRUE@USE_SQLITE=true
+@USE_BDB_TRUE@USE_BDB=true
 @BUILD_BITCOIN_CLI_TRUE@ENABLE_CLI=true
 @BUILD_BITCOIN_WALLET_TRUE@ENABLE_WALLET_TOOL=true
 @BUILD_BITCOIND_TRUE@ENABLE_BITCOIND=true