[UR] Improve handling of error cases in urProgramLink

[RossBrunton]

Note that this change includes a specification change: urProgramLink now requires the output parameter to contain either nullptr or some unspecified binary on failure.

As well as this change, a number of bugs have been fixed:

• The Level Zero adapter now correctly returns UR_RESULT_ERROR_PROGRAM_LINK_FAILURE when linking fails, rather than UR_RESULT_ERROR_UNKNOWN.
• A workaround has been added for some OpenCL devices that return CL_INVALID_BINARY rather than CL_LINK_PROGRAM_FAILURE on linker failure.
• The phProgram handle is wrapped in a loader handle by the loader even if an error would be returned. This is required by Level Zero, which outputs a "dummy" program to store the linker log.

Conformance tests have also been added.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 59 lines in your changes are missing coverage. Please review.

Project coverage is 12.41%. Comparing base (78ef1ca) to head (da9d876). Report is 190 commits behind head on main.

Files	Patch %	Lines
test/conformance/program/urProgramLink.cpp	0.00%	33 Missing :warning:
source/loader/ur_ldrddi.cpp	0.00%	10 Missing :warning:
source/adapters/null/ur_nullddi.cpp	0.00%	4 Missing :warning:
source/loader/layers/tracing/ur_trcddi.cpp	0.00%	4 Missing :warning:
source/loader/layers/validation/ur_valddi.cpp	0.00%	4 Missing :warning:
source/loader/ur_libapi.cpp	0.00%	4 Missing :warning:

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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1458      +/-   ##
==========================================
- Coverage   14.82%   12.41%   -2.41%     
==========================================
  Files         250      241       -9     
  Lines       36220    36293      +73     
  Branches     4094     4124      +30     
==========================================
- Hits         5369     4506     -863     
- Misses      30800    31783     +983     
+ Partials       51        4      -47     

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[kbenzie]

this has merged conflicts, please fix

[RossBrunton]

this has merged conflicts, please fix

Unfortunately the job in https://github.com/intel/llvm/pull/13085 is failing, so I'll need to look into that first when I get the chance.

[kbenzie]

this has merged conflicts, please fix

Unfortunately the job in intel/llvm#13085 is failing, so I'll need to look into that first when I get the chance.

I don't see how rebasing this PR requires investigation into the intel/llvm failures. Sure, to get it merged they would need to not fail but that shouldn't be a blocker for rebasing this PR.

[kbenzie]

@oneapi-src/unified-runtime-native-cpu-write please review