[QoI][stdlib] Improve some random call sites

[Azoy]

Instead of using generator directly, use Int.random(in:) to improve clarity of these call sites.

cc: @lorentey

Can you also kick off benchmarks as well?

[harlanhaskins]

@swift-ci please benchmark

[swift-ci]

Build comment file:

Code size: -Osize

TEST	OLD	NEW	DELTA	RATIO
Improvement
RandomShuffle.o	3831	3655	-4.6%	1.05x

How to read the data

The tables contain differences in performance which are larger than 8% and differences in code size which are larger than 1%.

If you see any unexpected regressions, you should consider fixing the regressions before you merge the PR.

Noise: Sometimes the performance results (not code size!) contain false alarms. Unexpected regressions which are marked with '(?)' are probably noise. If you see regressions which you cannot explain you can try to run the benchmarks again. If regressions still show up, please consult with the performance team (@eeckstein).

Hardware Overview

  Model Name: Mac Pro
  Model Identifier: MacPro6,1
  Processor Name: 12-Core Intel Xeon E5
  Processor Speed: 2.7 GHz
  Number of Processors: 1
  Total Number of Cores: 12
  L2 Cache (per Core): 256 KB
  L3 Cache: 30 MB
  Memory: 64 GB

---

[harlanhaskins]

@swift-ci please test

[swift-ci]

Build failed
Swift Test Linux Platform
Git Sha - 68a2a2c

[harlanhaskins]

Failure is unrelated, let's run the tests again.

@swift-ci please test

[lorentey]

Looking good!

[lorentey]

Microscopic nit: we can collapse these four lines into a single line now

[Azoy]

@harlanhaskins is this ready for merge?

[harlanhaskins]

Looks good to me!

@swift-ci please smoke test and merge

[Azoy]

@harlanhaskins I’m not sure CI picked that comment up. Try again?

[harlanhaskins]

@swift-ci please smoke test

[harlanhaskins]

Thanks, @Azoy!