Changes

[flang] Disallow INTENT attribute on procedure dummy arguments

C843 states that "An entity with the INTENT attribute shall be a dummy
data object or a dummy procedure pointer."  This change enforces that
and fixes some tests that erroneously violated this rule.

Differential Revision: https://reviews.llvm.org/D94781

[TargetLowering] Don't speculatively call ComputeNumSignBits. NFC

These methods are recursive so a little costly.

We only look at the result in one place in this function and it's
conditional. We also only need the second call if the first had
enough returned enough sign bits.

[flang][driver] Copy test file into a temp dir when testing (nfc)

The following driver invocation will generate an output file
in the same directory as the input file:

```
flang-new -fc1 -test-io test-input.f90
```

This is the desired behaviour. However, when testing we need to make
sure that we don't pollute the source directory. To this end, copy the
input file into a temporary directory before testing.

This is similar to https://reviews.llvm.org/D94243.

[clangd] Update CC Ranking model with better sampling.

A better sampling strategy was used to generate the dataset for this
model.
New signals introduced in this model:
- NumNameInContext: Number of words in the context that matches the name
of the candidate.
- FractionNameInContext: Fraction of the words in context matching the
name of the candidate.

We remove the signal `IsForbidden` from the model and down rank
forbidden signals aggresively.

Differential Revision: https://reviews.llvm.org/D94697