[stdlib] Remove optional comparison operators (SE-0121)

[jtbandes]

What's in this pull request?

An "implementation" (it's pretty much just deleting code) of SE-0121: removing the versions of <, <=, >, and >= which accept Optional operands.

---

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[CodaFi]

Congratulations on the proposal acceptance Jacob!

@swift-ci please test and merge.

[jtbandes]

Thanks! I haven't tested this with corelibs-foundation, so may have missed some uses. I guess we'll see :)

[jtbandes]

OK, I've created swiftlang/swift-package-manager#515 and swiftlang/swift-corelibs-foundation#459 to remove the few uses of these operators. Once those are merged we can re-run this build.

[jtbandes]

@CodaFi Can you re-trigger CI? Assuming it automatically pulls the latest swiftpm and corelibs-foundation, I think the build should work now.

[parkera]

@swift-ci Please test and merge

[jtbandes]

OK, another try @parkera, if you don't mind 😄

[gribozavr]

@swift-ci Please test and merge

[gribozavr]

@jtbandes

Foundation/IndexSet.swift:440:31: error: value of optional type 'Element?' not unwrapped; did you mean to use '!' or '?'?
        if range.lowerBound > last || (range.upperBound - 1) < first {

[jtbandes]

@gribozavr yep, I made a PR to fix that: swiftlang/swift-corelibs-foundation#464

[moiseev]

@swift-ci Please test and merge

[jtbandes]

@moiseev I think I've fixed the additional test failures. Building/testing locally now.

[gribozavr]

@swift-ci Please test and merge

[jtbandes]

Failure looks unrelated:

Command 2: "python" "/home/buildnode/jenkins/workspace/swift-PR-Linux/swift-integration-tests/repl/test-repl-glibc.py" "/home/buildnode/jenkins/workspace/swift-PR-Linux/buildbot_linux/none-swift_package_sandbox_linux-x86_64/usr/bin/swift"
Command 2 Result: 1
Command 2 Output:
None

Command 2 Stderr:
Traceback (most recent call last):
  File "/home/buildnode/jenkins/workspace/swift-PR-Linux/swift-integration-tests/repl/test-repl-glibc.py", line 35, in <module>
    repl.expect('\r\nhello, world.*\r\n')
  File "/usr/lib/python2.7/dist-packages/pexpect/__init__.py", line 1418, in expect
    timeout, searchwindowsize)
  File "/usr/lib/python2.7/dist-packages/pexpect/__init__.py", line 1433, in expect_list
    timeout, searchwindowsize)
  File "/usr/lib/python2.7/dist-packages/pexpect/__init__.py", line 1535, in expect_loop
    raise TIMEOUT(str(err) + '\n' + str(self))
pexpect.TIMEOUT: Timeout exceeded.

[jtbandes]

🎊