Add a helper method, in the PartialEvaluator class, for building a transfer map

[Snuffleupagus]

Currently we duplicate the same exact code twice, which seems unnecessary.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.19%. Comparing base (0f26334) to head (8a3c834).

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #21816      +/-   ##
==========================================
- Coverage   90.20%   90.19%   -0.01%     
==========================================
  Files         264      264              
  Lines       67339    67330       -9     
==========================================
- Hits        60741    60728      -13     
- Misses       6598     6602       +4     

Flag	Coverage Δ
browsertest	66.30% <100.00%> (-0.03%)	⬇️
fonttest	8.91% <ø> (ø)
integrationtest	69.40% <0.00%> (+<0.01%)	⬆️
unittest	58.36% <0.00%> (-0.01%)	⬇️
unittestcli	56.93% <0.00%> (+<0.01%)	⬆️

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[Snuffleupagus]

/botio browsertest

[moz-tools-bot]

From: Bot.io (Linux m4)

---

Received

Command cmd_browsertest from @Snuffleupagus received. Current queue size: 0

Live output at: http://54.241.84.105:8877/c66fe7d42872781/output.txt

[moz-tools-bot]

From: Bot.io (Windows)

---

Received

Command cmd_browsertest from @Snuffleupagus received. Current queue size: 0

Live output at: http://54.193.163.58:8877/33c7b94a42ea1ca/output.txt

[moz-tools-bot]

From: Bot.io (Linux m4)

---

Success

Full output at http://54.241.84.105:8877/c66fe7d42872781/output.txt

Total script time: 18.22 mins

• Regression tests: Passed

[moz-tools-bot]

From: Bot.io (Windows)

---

Success

Full output at http://54.193.163.58:8877/33c7b94a42ea1ca/output.txt

Total script time: 23.28 mins

• Regression tests: Passed

[timvandermeij]

Looks better indeed; thanks!