Remove the JIT EH/small code model tests for now.

These tests rely on two sections being allocated with a limited displacement
from one to the other to work. We've never guaranteed this, and consequently
these tests usually fail. That led to them being XFAILed, but now they XPASS
whenever the sections do happen to be allocated nearby in memory. So I'm
removing these for now to get rid of the noise. We can re-instate them if/when
we take the time to implement a displacement-respecting allocator.

llvm-svn: 284654