Fix verbose location reporting for internal assertions

[alexreinking]

This PR corrects the conditions on the printing of source location and condition information. For example, we now see the following when the error_bad_func_object test is run.

Internal error at /Users/areinking/dev/Halide/src/Func.cpp:88
Condition failed: func.get_contents().defined()
Error: Can't construct Func from undefined Function

When manually testing with user_assert, I can confirm that the extra information is printed when HL_DEBUG_CODEGEN is set to 1 or higher.

Fixes #8847

[TH3CHARLie]

Thanks! I verified locally and it's the expected behavior again