Fork and adapt old iree.compiler -> iree.compiler.tools. (iree-org#7164)

* Fork and adapt old iree.compiler -> iree.compiler.tools.

This is the first step to removing the original iree.compiler Python package in favor of the more full featured version developed under the dedicated iree-compiler-api project.

* Forks iree.compiler.[core|tf|tflite|xla] and support code to iree.compiler.tools
* Sets up temporary redirects from the root iree.compiler namespace so we have time to transition folks to new names.
* Adds a CAPI for invoking iree-translate as a function.
* Adds a standalone `ireec` binary and links it against the main CAPI shared library (ends up being 6KB on my machine).
* Sets up some testing for the project.

Include recursive package for core compiler tools. (iree-org#7153)

(Untested) follow-up to iree-org#6654 for the core tools (mainly `iree-translate`).

Attempting to fix an error demonstrated [in this notebook](https://colab.research.google.com/gist/ScottTodd/8403b5858224ad8e6e42c65c069b26af/iree-native-tools.ipynb):
```
!iree-translate --help

Traceback (most recent call last):
  File "/usr/local/bin/iree-translate", line 5, in <module>
    from iree.tools.core.scripts.iree_translate.__main__ import main
ModuleNotFoundError: No module named 'iree.tools.core.scripts'
```

We have validation for the pip installs and scripts now, but based on iree-org#6638 (comment), they should be running from a working directory other than where the pip install is?
https://github.com/google/iree/blob/dc13622f9aed080eb7096e0833925ce65d5d54ee/.github/workflows/validate_and_publish_release.yml#L41-L47

Use lld linker in CMake CI (iree-org#7152)

Fast is better than slow. The actual motivation for this came from
working on iree-org#7126 and noticing that
the link was really slow with gcc. The link is still really slow with
gcc, but I think this makes it better across the board.

Some ancillary cleanup was needed for this:
- pinning the `keras-nightly` pip package version, otherwise rebuilding
the docker image picked up the latest, even with a pinned tf-nightly.
- making the check for unsupported linker options more robust by also
testing the C compiler.

Limit fusion to ops with single uses to avoid duplication (iree-org#7103

)

Also move createResolveShapedTypeResultDimsPass before fusion

Introduce reverse op to LinalgExt dialect. (iree-org#7124)

Defines linalg_ext.reverse op and implements basic interface methods of
the op.

The reverse op in Linalg has Linalg unfriendly affine exprs, which
blocks tile and distribute transforms. This is a short/mid term solution
for tiling and distributing reverse ops.

It's a step toward iree-org#5045

Only add bundled pybind11 if not already found. (iree-org#7125)

* Needed for use of IREE as a sub-project that also configures pybind11.
* Enables building of IREE python bindings as part of iree-compiler-api.
* Fixes an issue with IREE data deps to make them relative to the project, not the root.
* Tweaks some settings on the compiler-api build to make it better for dev.

[spirv] Move Adreno matmul CodeGen config as SPIR-V default (iree-org…

…#7057)

This removes hand picked magic numbers and supports
more Vulkan targets.

[pydm] Add a basic RTL linker pass. (iree-org#7089)

* Includes build automation to produce the runtime library assembly file that the pass consumes.
* Not super complicated but gets the job done (and may be all this ever needs).
* Has the RTL builder do basic canonicalization (and verification) before saving.

Basic handling of multiple generic ops in dispatch regions on CPU pat…

…h. (iree-org#7102)

If there are no root operations within a dispatch region, assume all
generic ops are tiled + distributed the same way, and can therefore
use the same configuration.

NFC: Align python namespaces of iree-dialects and iree-compiler-api. (i…

…ree-org#7088)