Fix file descriptor leak when SQLite3 objects are garbage collected

Summary:
The SQLite3 native data classes were registered with NO_SWEEP flag, which
prevented their sweep methods from being called during request shutdown.
This caused file descriptors to leak when PHP code didn't explicitly
call $db->close() and the objects survived until request end.

Observed this in prod when comparing PDO and SQLite file descriptor usage

https://www.internalfb.com/phabricator/paste/view/P2169381411

# This Change
1. Adds sweep() methods to SQLite3, SQLite3Stmt, and SQLite3Result that
   properly clean up native SQLite resources
2. Updates destructors to call sweep() for consistent cleanup
3. Removes the NO_SWEEP flag so sweep is called during request shutdown

The sweep() implementation follows the same pattern used by PDO SQLite,
including proper handling of UDF Variants with releaseForSweep().

# Why NO_SWEEP was wrong
NO_SWEEP doesn't defer cleanup - it PREVENTS cleanup entirely for objects
that survive until request end. The memory is bulk-freed without calling
any cleanup functions, so native resources (file descriptors) leak.

Reviewed By: paulbiss

Differential Revision: D92496862

fbshipit-source-id: 5ed26749e770cc99c845b9b5741d9b4ab12b75a6

Author: Craig Phillips

hphp/runtime/ext/sqlite3/ext_sqlite3.cpp

@@ -167,9 +167,10 @@ static void php_sqlite3_callback_final(sqlite3_context *context) {
 SQLite3::SQLite3() : m_raw_db(nullptr) {
 }
 
-SQLite3::~SQLite3() {
+void SQLite3::sweep() {
   if (m_raw_db) {
     sqlite3_close_v2(m_raw_db);
+    m_raw_db = nullptr;
   }
 }
 
@@ -485,9 +486,10 @@ bool HHVM_METHOD(SQLite3, openblob, const String& /*table*/,
 SQLite3Stmt::SQLite3Stmt() : m_raw_stmt(nullptr) {
 }
 
-SQLite3Stmt::~SQLite3Stmt() {
+void SQLite3Stmt::sweep() {
   if (m_raw_stmt) {
     sqlite3_finalize(m_raw_stmt);
+    m_raw_stmt = nullptr;
   }
 }
 
@@ -774,7 +776,7 @@ static struct SQLite3Extension final : Extension {
     HHVM_ME(SQLite3, openblob);
     HHVM_STATIC_ME(SQLite3, version);
     HHVM_STATIC_ME(SQLite3, escapestring);
-    Native::registerNativeDataInfo<SQLite3>(Native::NDIFlags::NO_SWEEP);
+    Native::registerNativeDataInfo<SQLite3>();
 
     HHVM_ME(SQLite3Stmt, __construct);
     HHVM_ME(SQLite3Stmt, paramcount);
@@ -783,7 +785,7 @@ static struct SQLite3Extension final : Extension {
     HHVM_ME(SQLite3Stmt, clear);
     HHVM_ME(SQLite3Stmt, bindvalue);
     HHVM_ME(SQLite3Stmt, execute);
-    Native::registerNativeDataInfo<SQLite3Stmt>(Native::NDIFlags::NO_SWEEP);
+    Native::registerNativeDataInfo<SQLite3Stmt>();
 
     HHVM_ME(SQLite3Result, numcolumns);
     HHVM_ME(SQLite3Result, columnname);

hphp/runtime/ext/sqlite3/ext_sqlite3.h

@@ -26,7 +26,8 @@ namespace HPHP {
 
 struct SQLite3 : SystemLib::ClassLoader<"SQLite3"> {
   SQLite3();
-  ~SQLite3();
+  ~SQLite3() { sweep(); }
+  void sweep();
   void validate() const;
 
   struct UserDefinedFunc {
@@ -51,7 +52,8 @@ void HHVM_METHOD(SQLite3, open,
 
 struct SQLite3Stmt : SystemLib::ClassLoader<"SQLite3Stmt"> {
   SQLite3Stmt();
-  ~SQLite3Stmt();
+  ~SQLite3Stmt() { sweep(); }
+  void sweep();
   void validate() const;
 
   struct BoundParam {