Address flakiness of testSSLHandshakeErrorPropagation

Motivation:

Flaky tests are bad.

This test is flaky because the server closes the connection immediately
upon channelActive. In practice this can mean that the handshake never
even gets a chance to start: by the time the SSLHandler ends up
in the pipeline the connection is already dead. Heck, by the time we
attempt to complete the connection the connection might be dead.

Modifications:

- Change the shutdown to be on first read.
- Remove the disabled autoRead.
- Change the expected NIOTS failure mode to connectTimeout,
    which is how this manifests in NIOTS.

Result:

Test is no longer flaky.

Author: Lukasa

Tests/AsyncHTTPClientTests/HTTPClientTests.swift

@@ -2680,13 +2680,12 @@ class HTTPClientTests: XCTestCase {
         class CloseHandler: ChannelInboundHandler {
             typealias InboundIn = Any
 
-            func channelActive(context: ChannelHandlerContext) {
+            func channelRead(context: ChannelHandlerContext) {
                 context.close(promise: nil)
             }
         }
 
         let server = try ServerBootstrap(group: self.serverGroup)
-            .childChannelOption(ChannelOptions.autoRead, value: false)
             .childChannelInitializer { channel in
                 channel.pipeline.addHandler(CloseHandler())
             }
@@ -2697,15 +2696,23 @@ class HTTPClientTests: XCTestCase {
             XCTAssertNoThrow(try server.close().wait())
         }
 
+        // We set the connect timeout down very low here because on NIOTS this manifests as a connect
+        // timeout.
+        let config = HTTPClient.Configuration(timeout: HTTPClient.Configuration.Timeout(connect: .milliseconds(100), read: nil))
+        let client = HTTPClient(eventLoopGroupProvider: .shared(self.clientGroup), configuration: config)
+        defer {
+            XCTAssertNoThrow(try client.syncShutdown())
+        }
+
         let request = try Request(url: "https://localhost:\(server.localAddress!.port!)", method: .GET)
-        let task = self.defaultClient.execute(request: request, delegate: TestHTTPDelegate())
+        let task = client.execute(request: request, delegate: TestHTTPDelegate())
 
         XCTAssertThrowsError(try task.wait()) { error in
             #if os(Linux)
                 XCTAssertEqual(error as? NIOSSLError, NIOSSLError.uncleanShutdown)
             #else
                 if isTestingNIOTS() {
-                    XCTAssertEqual((error as? AsyncHTTPClient.HTTPClient.NWTLSError).map { $0.status }, errSSLClosedNoNotify)
+                    XCTAssertEqual((error as? ChannelError), .connectTimeout(.milliseconds(100)))
                 } else {
                     XCTAssertEqual((error as? IOError).map { $0.errnoCode }, 54)
                 }