avcodec/aacdec_fixed: fix: left shift of negative value -1

Fixes: 2699/clusterfuzz-testcase-minimized-5631303862976512

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/aacdec_fixed.c

@@ -432,7 +432,7 @@ static void apply_independent_coupling_fixed(AACContext *ac,
     else {
       for (i = 0; i < len; i++) {
           tmp = (int)(((int64_t)src[i] * c + (int64_t)0x1000000000) >> 37);
-          dest[i] += tmp << shift;
+          dest[i] += tmp * (1 << shift);
       }
     }
 }