[SR-7076] Make ContiguousArray Codable

[anayini]

Implements Encodable and Decodable for ContiguousArray.

Resolves SR-7076.

[anayini]

Trying to run tests locally as well, but having some build issues...might be because I'm on 10.14...

[xwu]

A formatting point: please use two spaces for indents in this file (and throughout the stdlib).

[anayini]

@xwu - Thank you for the quick feedback! Looks like I applied the fix then rebased onto the upstream where the @inlinable had been removed.

[anayini]

@xwu - Are you able to trigger the tests?

[xwu]

Sure, but this PR needs to have some tests first before that'd be meaningful, no?

[anayini]

@xwu - Yeah figured still made sense to run the smoke tests. I looked around a bit and couldn't find the spot where Codable tests were for Array and what not (wasn't sure there was a great example for the above in CodableTests). Definitely happy to add a test to the appropriate spot if I can get some guidance as to where to put those / examples of similar ones!

[anayini]

@airspeedswift - Do we still want to move forward with this or shall I close?

[jrose-apple]

Post-break ping for @airspeedswift and maybe @lorentey.

[moiseev]

@swift-ci Please test

[moiseev]

@anayini thanks for implementing this. Do you mind adding a simple test as a follow-up PR?

[anayini]

@moiseev can do - can you help point me toward a similar Codable test? Was looking for one in the above comments that I could base my test off of.

[benrimmington]

@anayini A simple test would be similar to the existing Locale and TimeZone tests.

You could test ContiguousArray<String> literals with different numbers of elements.

The contents of the TestCodable class and tests dictionary are arranged alphabetically.

[dlbuckley]

@anayini you can see the Codable tests that I've added for the Range conformance in
#19532

The instructions to run the tests can be found here.

I was using a command like utils/build-script --release --test or similar to run the tests when I was adding the conformance for the Range types. It takes a while the first time but subsequent runs are much faster.

[anayini]

Thanks @dlbuckley @benrimmington! Will try to get to it this weekend!