[clang][utils] Remove ClangDataFormat.py for now (llvm#96385)

This formatter doesn't currently provide much value. It only formats
`SourceLocation` and `QualType`. The only formatting it does for
`QualType` is call `getAsString()` on it.

The main motivator for the removal however is that the formatter
implementation can be very slow (since it uses the expression evaluator
in non-trivial ways).

Not infrequently do we get reports about LLDB being slow when debugging
Clang, and it turns out the user was loading `ClangDataFormat.py` in
their `.lldbinit` by default.

We should eventually develop proper formatters for Clang data-types, but
these are currently not ready. So this patch removes them in the
meantime to avoid users shooting themselves in the foot, and giving the
wrong impression of these being reference implementations.

Author: Michael137