Frame scaling loop restoration crash fix

`av1_init_lr_mt_buffers()`: Get the actual number of workers from
`lr_sync` struct instead of recomputing the value with
`av1_get_num_mod_workers_for_alloc()`, which might be incorrect.

Added unit test that verifies this fix.

Fix was proposed by Wan-Teh Chang.

Changes beyond the cherry-pick:
- Deleted the line "cfg_.use_fixed_qp_offsets = 2;" because
  use_fixed_qp_offsets == 2 is not supported on the opaline branch.
- Changed AOM_TUNE_IQ to AOM_TUNE_SSIM because AOM_TUNE_IQ cannot
  be used in good-quality mode on the opaline branch.

Change-Id: Iaae2bed44a112ac16c11b8561024e5166587a9b6
(cherry picked from commit 4cc0867f261f46d00b2ddb27b4de70d8e8e4552e)

av1/encoder/ethread.c

diff --git a/av1/encoder/ethread.c b/av1/encoder/ethread.c
index fb6a13a..2ffd6ee 100644
--- a/av1/encoder/ethread.c
+++ b/av1/encoder/ethread.c
@@ -834,9 +834,7 @@
   if (lr_sync->sync_range) {
     if (cpi->ppi->gf_group.frame_parallel_level[cpi->gf_frame_index] > 0)
       return;
-    int num_lr_workers =
-        av1_get_num_mod_workers_for_alloc(&cpi->ppi->p_mt_info, MOD_LR);
-    assert(num_lr_workers <= lr_sync->num_workers);
+    int num_lr_workers = lr_sync->num_workers;
     lr_sync->lrworkerdata[num_lr_workers - 1].rst_tmpbuf = cm->rst_tmpbuf;
     lr_sync->lrworkerdata[num_lr_workers - 1].rlbs = cm->rlbs;
   }

test/resize_test.cc

diff --git a/test/resize_test.cc b/test/resize_test.cc
index 901bc12..4923d4e 100644
--- a/test/resize_test.cc
+++ b/test/resize_test.cc
@@ -348,6 +348,67 @@
 }
 
 #if !CONFIG_REALTIME_ONLY
+class ResizeCrashTest : public ::libaom_test::CodecTestWithParam<int>,
+                        public ::libaom_test::EncoderTest {
+ protected:
+  ResizeCrashTest() : EncoderTest(GET_PARAM(0)) {}
+
+  ~ResizeCrashTest() override = default;
+
+  void SetUp() override {
+    cpu_used_ = GET_PARAM(1);
+
+    InitializeConfig(::libaom_test::kOnePassGood);
+  }
+
+  void PreEncodeFrameHook(libaom_test::VideoSource *video,
+                          libaom_test::Encoder *encoder) override {
+    if (video->frame() == 0) {
+      encoder->Control(AOME_SET_CPUUSED, cpu_used_);
+      encoder->Control(AOME_SET_TUNING, AOM_TUNE_SSIM);
+      encoder->Control(AOME_SET_CQ_LEVEL, first_frame_cq_level_);
+      encoder->Control(AV1E_SET_ROW_MT, 1);
+      encoder->Control(AV1E_SET_TILE_COLUMNS, first_tile_rows_cols_);
+      encoder->Control(AV1E_SET_TILE_ROWS, first_tile_rows_cols_);
+      encoder->Control(AV1E_SET_COLOR_RANGE, AOM_CR_FULL_RANGE);
+
+      struct aom_scaling_mode mode = { AOME_ONETWO, AOME_ONETWO };
+      encoder->Control(AOME_SET_SCALEMODE, &mode);
+    } else {
+      encoder->Control(AOME_SET_CQ_LEVEL, second_frame_cq_level_);
+      encoder->Control(AV1E_SET_TILE_COLUMNS, second_tile_rows_cols_);
+      encoder->Control(AV1E_SET_TILE_ROWS, second_tile_rows_cols_);
+      struct aom_scaling_mode mode = { AOME_NORMAL, AOME_NORMAL };
+      encoder->Control(AOME_SET_SCALEMODE, &mode);
+    }
+  }
+
+  int cpu_used_;
+  int first_frame_cq_level_;
+  int second_frame_cq_level_;
+  int first_tile_rows_cols_;
+  int second_tile_rows_cols_;
+};
+
+// Recreate the restoration filter crash that was
+// fixed by https://aomedia-review.googlesource.com/c/aom/+/208901
+TEST_P(ResizeCrashTest, TestRestorationFilterCrash) {
+  ::libaom_test::Y4mVideoSource video("rush_hour_444.y4m", 0, 2);
+  cfg_.g_lag_in_frames = 0;
+  cfg_.g_profile = 1;
+  cfg_.g_bit_depth = AOM_BITS_8;
+  cfg_.g_input_bit_depth = 8;
+  cfg_.g_threads = 14;
+  cfg_.rc_end_usage = AOM_Q;
+
+  first_frame_cq_level_ = 59;
+  second_frame_cq_level_ = 59;
+  first_tile_rows_cols_ = 1;
+  second_tile_rows_cols_ = 0;
+
+  ASSERT_NO_FATAL_FAILURE(RunLoop(&video));
+}
+
 const unsigned int kStepDownFrame = 3;
 const unsigned int kStepUpFrame = 6;
 
@@ -1178,6 +1239,7 @@
 AV1_INSTANTIATE_TEST_SUITE(ResizeTest,
                            ::testing::Values(::libaom_test::kRealTime,
                                              ::libaom_test::kOnePassGood));
+AV1_INSTANTIATE_TEST_SUITE(ResizeCrashTest, ::testing::Values(3));
 #endif
 
 AV1_INSTANTIATE_TEST_SUITE(ResizeRealtimeTest,