Initialize a ModuleStateTracker at most once per BasicBlock instead of
once per Instruction. When the CFG info is provided, it is initialized
once per function.

Add functions to print the CFG via the debugger using a specified
filename.

This is useful when comparing CFGs for the same function before vs after
a change, or when handling functions with names that are too long to be
file names.

This pass has no test coverage in upstream LLVM, is not used anywhere in
upstream LLVM, and has a NewPM equivalent. For these reasons, remove it.

This pass has no test coverage upstream, is not used anywhere upstream,
and has a NewPM equivalent. For these reasons, remove it.

This pass has a NewPM equivalent, isn't used anywhere upstream, and
doesn't have any test coverage. For these reasons, remove it.

This pass isn't used anywhere upstream, has a NewPM equivalent, and has
no test coverage. For these reasons, remove it.

The `BlockFrequency` class abstracts `uint64_t` frequency values. Use it
more consistently in various APIs and disable implicit conversion to
make usage more consistent and explicit.

- Use `BlockFrequency Freq` parameter for `setBlockFreq`,
`getProfileCountFromFreq` and `setBlockFreqAndScale` functions.
- Return `BlockFrequency` in `getEntryFreq()` functions.
- While on it change some `const BlockFrequency& Freq` parameters to
plain `BlockFreqency Freq`.
- Mark `BlockFrequency(uint64_t)` constructor as explicit.
- Add missing `BlockFrequency::operator!=`.
- Remove `uint64_t BlockFreqency::getMaxFrequency()`.
- Add `BlockFrequency BlockFrequency::max()` function.

Number of lines output by preprocessor:
before: 1065940348
after:  1065307662

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D120659

Currently the value is only used when calling `F->viewCFG()` which is missing out on its potential and usefulness.
So I added the check to the printer passes as well.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D102011