[hec-assembler]: Linking multi *.mem programs with trace_file

[joserochh]

Proposed changes

Enables the linking of multiple kernels with individual memory mapping files by using multi_op trace file.

Types of changes

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update (if none of the other choices apply)

Checklist

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• I have added tests that prove my fix is effective or that my feature works (if appropriate)
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• Any dependent changes have been merged and published in downstream modules

Further comments

• Enabled caching for kernel loading so kernel files don't need to be parsed multiple times if the same kernel operation is used across the overall program.
• Input prefixes are extracted from the trace file information. So, a naming convention is assumed.
• Individual kernel variables are mapped to names used in the trace file. So, a naming convention for poly variables is assumed.
• Refactored he_link.py taking some helper methods and structures out of this file.
• Refactored loaded.py to be a class.
• Refactored NamedTuple KernelFiles to simple class KernelInfo.
• Unit test coverage up to 90% on linker module.

[kylanerace]

LGTM, will require extensive testing to check differences between separately scheduled and jointly scheduled workloads

[christopherngutierrez]

LGTM, tested locally.