Identified with misc-include-cleaner.

With the IR extension added to MD_prof branch weights, we can now easily
distinguish between weights added by `llvm.expect*` intrinsics and
weights from other sources. This patch re-enables the assert checking
for malformed metadata, which should never happen using the
`llvm.expect*` family of intrinsics.

Pull Request: https://github.com/llvm/llvm-project/pull/90670

MisExpect was occasionally crashing under SampleProfiling, due to a division by zero.
We worked around that in D124302 by changing the assert to an early return.
This patch is intended to add a test case for the crashing scenario and
re-enable MisExpect for SampleProfiling.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D124481

Use `std::clamp` directly from the standard library now that LLVM is built with
C++17 standards mode.

Differential Revision: https://reviews.llvm.org/D131869

In D131869 we noticed that we jump through some hoops because we parse the
tolerance option used in MisExpect.cpp into a 64-bit integer. This is
unnecessary, since the value can only be in the range [0, 100).

This patch changes the underlying type to be 32-bit from where it is
parsed in Clang through to it's use in LLVM.

Reviewed By: jloser

Differential Revision: https://reviews.llvm.org/D131935

In this patch we replace common code patterns with the use of utility
functions for dealing with profiling metadata. There should be no change
in functionality, as the existing checks should be preserved in all
cases.

Reviewed By: bogner, davidxl

Differential Revision: https://reviews.llvm.org/D128860

This reverts commit 300c9a78819b4608b96bb26f9320bea6b8a0c4d0.

We will reland once these issues are ironed out.