[SNOW-3249917] JDBC removal Step 11a (part 2): Replicate HttpUtil, swap callers to replicated REST infrastructure

Replicate JDBC's HttpUtil as JdbcHttpUtil (renamed to avoid collision with
ingest's existing net.snowflake.ingest.utils.HttpUtil). Also replicate
SnowflakeMutableProxyRoutePlanner and AttributeEnhancingHttpRequestRetryHandler
as small helper classes.

Key changes:
- JdbcHttpUtil: verbatim replication of JDBC HttpUtil with import swaps.
  SFTrustManager replaced with null (ingest does not use OCSP trust manager).
  SFSSLConnectionSocketFactory -> IngestSSLConnectionSocketFactory.
  SystemUtil.convertSystemPropertyToIntValue inlined.
  SessionUtil.isNewRetryStrategyRequest inlined as static method.
  Deprecated S3 proxy wrapper methods omitted (S3HttpUtil callable directly).

- RestRequest: all FQN net.snowflake.client.core.HttpUtil references replaced
  with JdbcHttpUtil. SessionUtil.isNewRetryStrategyRequest replaced with
  JdbcHttpUtil.isNewRetryStrategyRequest.

- TelemetryClient: HttpUtil.executeGeneralRequest and HttpUtil.getSocketTimeout
  replaced with JdbcHttpUtil equivalents. SnowflakeSQLException import swapped
  to ingest's replicated version.

- SnowflakeGCSClient: HttpUtil.getHttpClient, getHttpClientWithoutDecompression,
  getSocketTimeout replaced with JdbcHttpUtil equivalents. Added toIngestKey
  adapter to convert JDBC's HttpClientSettingsKey during transition.

- SnowflakeAzureClient: setSessionlessProxyForAzure import swapped from JDBC
  HttpUtil to JdbcHttpUtil.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sfc-gh-ggeng

.plans/JDBC_REMOVAL_PLAN.md

@@ -12,6 +12,8 @@ eliminate the JDBC dependency entirely.
 
 **This project is a pure mechanical migration. There must be no functional changes.**
 
+- **Always replicate** — no matter how many dependencies, replicate the JDBC original
+  verbatim. Never create "simplified replacements" or "minimal viable alternatives."
 - Copy JDBC classes verbatim into this repo. Compare against the actual source file
   in the JDBC repo (not decompiled output). Do not refactor, simplify, rename fields,
   change method signatures, strip comments/Javadoc, or improve logic — even where

src/main/java/net/snowflake/ingest/connection/telemetry/TelemetryClient.java

@@ -11,9 +11,9 @@
 import java.util.LinkedList;
 import java.util.Objects;
 import java.util.concurrent.Future;
-import net.snowflake.client.core.HttpUtil;
-import net.snowflake.client.jdbc.SnowflakeSQLException;
+import net.snowflake.ingest.streaming.internal.fileTransferAgent.JdbcHttpUtil;
 import net.snowflake.ingest.streaming.internal.fileTransferAgent.ObjectMapperFactory;
+import net.snowflake.ingest.streaming.internal.fileTransferAgent.SnowflakeSQLException;
 import net.snowflake.ingest.streaming.internal.fileTransferAgent.TelemetryThreadPool;
 import net.snowflake.ingest.streaming.internal.fileTransferAgent.log.SFLogger;
 import net.snowflake.ingest.streaming.internal.fileTransferAgent.log.SFLoggerFactory;
@@ -275,11 +275,11 @@ private boolean sendBatch() throws IOException {
 
       try {
         response =
-            HttpUtil.executeGeneralRequest(
+            JdbcHttpUtil.executeGeneralRequest(
                 post,
                 TELEMETRY_HTTP_RETRY_TIMEOUT_IN_SEC,
                 0,
-                (int) HttpUtil.getSocketTimeout().toMillis(),
+                (int) JdbcHttpUtil.getSocketTimeout().toMillis(),
                 0,
                 this.httpClient);
         stopwatch.stop();

src/main/java/net/snowflake/ingest/streaming/internal/fileTransferAgent/AttributeEnhancingHttpRequestRetryHandler.java

@@ -0,0 +1,32 @@
+/*
+ * Replicated from snowflake-jdbc (v3.25.1)
+ * Source: https://github.com/snowflakedb/snowflake-jdbc/blob/v3.25.1/src/main/java/net/snowflake/client/core/AttributeEnhancingHttpRequestRetryHandler.java
+ *
+ * Permitted differences: package declaration.
+ */
+package net.snowflake.ingest.streaming.internal.fileTransferAgent;
+
+import java.io.IOException;
+import org.apache.http.impl.client.DefaultHttpRequestRetryHandler;
+import org.apache.http.protocol.HttpContext;
+
+/**
+ * Extends {@link DefaultHttpRequestRetryHandler} to store the current execution count (attempt
+ * number) in the {@link HttpContext}. This allows interceptors to identify retry attempts.
+ *
+ * <p>The execution count is stored using the key defined by {@link #EXECUTION_COUNT_ATTRIBUTE}.
+ */
+class AttributeEnhancingHttpRequestRetryHandler extends DefaultHttpRequestRetryHandler {
+  /**
+   * The key used to store the current execution count (attempt number) in the {@link HttpContext}.
+   * Interceptors can use this key to retrieve the count. The value stored will be an {@link
+   * Integer}.
+   */
+  static final String EXECUTION_COUNT_ATTRIBUTE = "net.snowflake.client.core.execution-count";
+
+  @Override
+  public boolean retryRequest(IOException exception, int executionCount, HttpContext context) {
+    context.setAttribute(EXECUTION_COUNT_ATTRIBUTE, executionCount);
+    return super.retryRequest(exception, executionCount, context);
+  }
+}