Changes

Reland "[LLD] Remove global state in lld/COFF" after fixing asan and msan test failures

Original commit description:

  [LLD] Remove global state in lld/COFF

  This patch removes globals from the lldCOFF library, by moving globals
  into a context class (COFFLinkingContext) and passing it around wherever
  it's needed.

  See https://lists.llvm.org/pipermail/llvm-dev/2021-June/151184.html for
  context about removing globals from LLD.

  I also haven't moved the `driver` or `config` variables yet.

  Differential Revision: https://reviews.llvm.org/D109634

This reverts commit a2fd05ada9030eab2258fff25e77a05adccae128.

Original commits were b4fa71eed34d967195514fe9b0a5211fca2bc5bc
and e03c7e367adb8f228332e3c2ef8f45484597b719.

[mlir] Fix syntax example for tensor.from_elements

Parens are not used here

[lld] Fix small error in previous commit
6f7483b1ece4747f2aafe4baa05fc07e7dc9ed9d.

[OpenMP] Change debugging symbol to weak_odr linkage

The new device runtime uses an internal variable to set debugging. This
variable was originally privately linked because every module will have
a copy of it. This caused problems with merging the device bitcode
library because it would get renamed and there was not a way to refer to
an external, private symbol. This changes the symbol to weak_odr so it
can be defined multiply, but will not be renamed.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D109997

[OpenMP] Implement __assert_fail in the new device runtime

This patch implements the `__assert_fail` function in the new device
runtime. This allows users and developers to use the standars assert
function inside of the device.

Reviewed By: tianshilei1992

Differential Revision: https://reviews.llvm.org/D109886

[OpenMP] Add additional fields to device environment

This patch adds fields for the device number and number of devices into
the device environment struct and debugging values.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D110004

[OpenMP] Add support for dynamic shared memory in new RTL

This patch adds support for using dynamic shared memory in the new
device runtime. The new function `__kmpc_get_dynamic_shared` will return a
pointer to the buffer of dynamic shared memory. Currently the amount of memory
allocated is set by an environment variable.

In the future this amount will be added to the amount used for the smart stack
which will be configured in a similar way.

Reviewed By: tianshilei1992

Differential Revision: https://reviews.llvm.org/D110006

Check for invalid projects passed in LLVM_ENABLE_PROJECTS

This is catching misconfiguration. For example one of my automation
had a typo running `-DLLVM_ENABLE_PROJECTS=nlir` and it was just
silently ignored. Instead, an error will now be displayed.

Differential Revision: https://reviews.llvm.org/D110016