Python3 compatibility for Benchmarks

[tbkka]

Three issues addressed here:

1. Dependency on dictionary iteration order

CharacterProperties.swift.gyb iterated a dictionary to produce its output.
Changed this to a list of tuples to ensure the order is predictable.
Regenerated CharacterProperties.swift to match the new order.

2. Python3 map returns an iterator, not a list

Changed a bunch of map calls to list(map(...)) to ensure the result is a list

3. Python3 int() expects a string, won't accept a list of characters

Added a concatenation step that is effectively a no-op on Python2

[tbkka]

@swift-ci Please smoke test

[tbkka]

@swift-ci Please benchmark

[swift-ci]

Performance: -O

Regression	OLD	NEW	DELTA	RATIO
FlattenListFlatMap	3679	4526	+23.0%	0.81x (?)

Code size: -O

Performance: -Osize

Improvement	OLD	NEW	DELTA	RATIO
ObjectiveCBridgeStubToNSDate2	360	330	-8.3%	1.09x (?)
ObjectiveCBridgeStubToNSDateRef	2380	2200	-7.6%	1.08x (?)

Code size: -Osize

Performance: -Onone

Code size: -swiftlibs

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 mini
  Model Identifier: Macmini8,1
  Processor Name: 6-Core Intel Core i7
  Processor Speed: 3.2 GHz
  Number of Processors: 1
  Total Number of Cores: 6
  L2 Cache (per Core): 256 KB
  L3 Cache: 12 MB
  Memory: 64 GB

[tbkka]

@swift-ci Please test

[tbkka]

@swift-ci Python lint