Increase scaling in linsolve_wiener

Reduces likelihood of overflows and re-enables previously
disabled overflow tests.

Bug: b:330639949, oss-fuzz:68195

Change-Id: I2c3dc9bd5783836d65b3c7a4452061b27cf4c82c
(cherry picked from commit 22bcd3de8f4fc43c4e87ef9dedfb40594fb1569b)

av1/encoder/pickrst.c

diff --git a/av1/encoder/pickrst.c b/av1/encoder/pickrst.c
index b0d0d0b..53a70e4 100644
--- a/av1/encoder/pickrst.c
+++ b/av1/encoder/pickrst.c
@@ -1176,7 +1176,7 @@
       if (abs_akj > max_abs_akj) max_abs_akj = abs_akj;
     }
     const int scale_threshold = 1 << 22;
-    const int scaler_A = max_abs_akj < scale_threshold ? 1 : (1 << 5);
+    const int scaler_A = max_abs_akj < scale_threshold ? 1 : (1 << 6);
     const int scaler_c = max_abs_akj < scale_threshold ? 1 : (1 << 7);
     const int scaler = scaler_c * scaler_A;
 

test/wiener_test.cc

diff --git a/test/wiener_test.cc b/test/wiener_test.cc
index 052f095..467507f 100644
--- a/test/wiener_test.cc
+++ b/test/wiener_test.cc
@@ -1693,7 +1693,7 @@
 
 // A test that reproduces crbug.com/oss-fuzz/68195: signed integer overflow in
 // linsolve_wiener().
-TEST(SearchWienerTest, DISABLED_8bitSignedIntegerOverflowInLinsolveWiener) {
+TEST(SearchWienerTest, 8bitSignedIntegerOverflowInLinsolveWiener) {
   constexpr int kWidth = 4;
   constexpr int kHeight = 3;
   constexpr unsigned char kBuffer[kWidth * kHeight] = {
@@ -1861,7 +1861,7 @@
 
 // A test that reproduces b/330639949: signed integer overflow in
 // linsolve_wiener().
-TEST(SearchWienerTest, DISABLED_12bitSignedIntegerOverflowInLinsolveWiener) {
+TEST(SearchWienerTest, 12bitSignedIntegerOverflowInLinsolveWiener) {
   constexpr int kWidth = 173;
   constexpr int kHeight = 3;
   // Since the image format is YUV 4:2:0, aom_img_wrap() expects the buffer is