Revert "[lldb] Add support for evaluating expressions in static member functions"

This reverts commit 00764c36 and the
follow up d2223c7a.

The original patch broke that one could use static member variables while
inside a static member functions without having a running target. It seems that
LLDB currently requires that static variables are only found via the global
variable lookup so that they can get materialized and mapped to the argument
struct of the expression.

After 00764c36 static variables of the current
class could be found via Clang's lookup which LLDB isn't observing. This
resulting in expressions actually containing these variables as normal
globals that can't be rewritten to a member of the argument struct.

More specifically, in the test TestCPPThis, the expression
`expr --j false -- s_a` is now only passing if we have a runnable target.

I'll revert the patch as the possible fixes aren't trivial and it degrades
the debugging experience more than the issue that the revert patch addressed.

The underlying bug can be reproduced before/after this patch by stopping
in `TestCPPThis` main function and running: `e -j false -- my_a; A<int>::s_a`.
The `my_a` will pull in the `A<int>` class and the second expression will
be resolved by Clang on its own (which causes LLDB to not materialize the
static variable).

Note: A workaround is to just do `::s_a` which will force LLDB to take the global
variable lookup.