BaseTools: Fix raw strings containing valid escape characters

[Javagedes]

Description

Fixes raw regex strings that contain valid (and purposeful) escape characters as they are being treated as individual characters rather than the single escaped character they represent (i.e. '\t' is being treated as a '\' and a 't' rather than a single tab character).

Note: This is the same patch series being added via https://edk2.groups.io/g/devel/message/112986, but seeing as this is a breaking change being seen by partners, I figured we should get this into MU_BASECORE as quickly as possible.

• Impacts functionality?
  • Functionality - Does the change ultimately impact how firmware functions?
  • Examples: Add a new library, publish a new PPI, update an algorithm, ...
• Impacts security?
  • Security - Does the change have a direct security impact on an application,
    flow, or firmware?
  • Examples: Crypto algorithm change, buffer overflow fix, parameter
    validation improvement, ...
• Breaking change?
  • Breaking change - Will anyone consuming this change experience a break
    in build or boot behavior?
  • Examples: Add a new library class, move a module to a different repo, call
    a function in a new library class in a pre-existing module, ...
• Includes tests?
  • Tests - Does the change include any explicit test code?
  • Examples: Unit tests, integration tests, robot tests, ...
• Includes documentation?
  • Documentation - Does the change contain explicit documentation additions
    outside direct code modifications (and comments)?
  • Examples: Update readme file, add feature readme file, link to documentation
    on an a separate Web page, ...

How This Was Tested

Verified on multiple partner platforms

Integration Instructions

N/A

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (005055b) 1.87% compared to head (76dd051) 1.87%.

Additional details and impacted files

@@               Coverage Diff               @@
##           release/202302     #663   +/-   ##
===============================================
  Coverage            1.87%    1.87%           
===============================================
  Files                1341     1341           
  Lines              286451   286451           
  Branches             5765     5765           
===============================================
  Hits                 5359     5359           
  Misses             281042   281042           
  Partials               50       50           

Flag	Coverage Δ
CryptoPkg	7.36% <ø> (ø)
MdeModulePkg	0.72% <ø> (ø)
MdePkg	3.61% <ø> (ø)
PolicyServicePkg	30.20% <ø> (ø)
UefiCpuPkg	5.18% <ø> (ø)
UnitTestFrameworkPkg	∅ <ø> (∅)

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