The use of `-lobjc` resulted in this test failing to build on Linux. The
flag is not necessary, this removes the flag with the expectation it
will fix the test on Linux.
Use the current frame's language to lookup commands provided by language plugins.
This means commands like `language {objc,cplusplus} <command>` can be used directly, without using the `language <lang>` prefix.
For example, when stopped on a C++ frame, `demangle _Z1fv` will run `language cplusplus demangle _Z1fv`.
rdar://149882520