Fix OOM issue when setting concurrentHTTP1ConnectionsPerHostSoftLimit to Int.max (#763)

### Motivation:

When a user wishes to make the connection pool create as many concurrent
connections as possible, a natural way to achieve this would be to set
`.max` to the `concurrentHTTP1ConnectionsPerHostSoftLimit` property.

```swift
HTTPClient.Configuration().connectionPool = .init(
    idleTimeout: .hours(1),
    concurrentHTTP1ConnectionsPerHostSoftLimit: .max
)
```

The `concurrentHTTP1ConnectionsPerHostSoftLimit` property is of type
`Int`. Setting it to `Int.max` leads to `Int.max` being passed as an
argument to `Array`s `.reserveCapacity(_:)` method, causing an OOM
issue.

Addresses Github Issue #751 

### Modifications:

Capped the argument to `self.connections.reserveCapacity(_:)` to 1024 in
`HTTPConnectionPool.HTTP1Connections`

### Result:

Users can now set the `concurrentHTTP1ConnectionsPerHostSoftLimit`
property to `.max` without causing an OOM issue.

Author: aryan-25

Sources/AsyncHTTPClient/ConnectionPool/State Machine/HTTPConnectionPool+HTTP1Connections.swift

@@ -261,7 +261,7 @@ extension HTTPConnectionPool {
 
         init(maximumConcurrentConnections: Int, generator: Connection.ID.Generator, maximumConnectionUses: Int?) {
             self.connections = []
-            self.connections.reserveCapacity(maximumConcurrentConnections)
+            self.connections.reserveCapacity(min(maximumConcurrentConnections, 1024))
             self.overflowIndex = self.connections.endIndex
             self.maximumConcurrentConnections = maximumConcurrentConnections
             self.generator = generator

Tests/AsyncHTTPClientTests/AsyncAwaitEndToEndTests.swift

@@ -642,6 +642,24 @@ final class AsyncAwaitEndToEndTests: XCTestCase {
         }
     }
 
+    func testInsanelyHighConcurrentHTTP1ConnectionLimitDoesNotCrash() async throws {
+        let bin = HTTPBin(.http1_1(compress: false))
+        defer { XCTAssertNoThrow(try bin.shutdown()) }
+
+        var httpClientConfig = HTTPClient.Configuration()
+        httpClientConfig.connectionPool = .init(
+            idleTimeout: .hours(1),
+            concurrentHTTP1ConnectionsPerHostSoftLimit: Int.max
+        )
+        httpClientConfig.timeout = .init(connect: .seconds(10), read: .seconds(100), write: .seconds(100))
+
+        let httpClient = HTTPClient(eventLoopGroupProvider: .shared(self.clientGroup), configuration: httpClientConfig)
+        defer { XCTAssertNoThrow(try httpClient.syncShutdown()) }
+
+        let request = HTTPClientRequest(url: "http://localhost:\(bin.port)")
+        _ = try await httpClient.execute(request, deadline: .now() + .seconds(2))
+    }
+
     func testRedirectChangesHostHeader() {
         XCTAsyncTest {
             let bin = HTTPBin(.http2(compress: false))