Fix two IRGen tests that are failing on Android armv7 and disable eight ClangImporter, C++ Interop, and SILOptimizer tests, two of which that were already failing on other 32-bit platforms.
Use the `%target-swift-5.1-abi-triple` substitution to compile the tests for
deployment to the minimum OS versions required for use of _Concurrency APIs,
instead of disabling availability checking.
