[C++][FlightRPC][ODBC] Use static test linkage for Linux ODBC

[alinaliBQ]

Describe the enhancement requested

Both Arrow Flight SQL ODBC and the ODBC test executable link to bundled gRPC, and that causes segmentation fault when the ODBC is trying to connect to a gRPC-based mock server.
The solution is to pass ARROW_TEST_LINKAGE=static for the ODBC tests on Linux, so the odbc tests on Linux link to just one set of gRPC symbols.

Out of scope: Enabling Linux tests in CI, it will be a separate GitHub issue.

Component(s)

FlightRPC, C++