Fix that `shouldUseWeakMemoryCache` code was lost during merge conflict

SDWebImage/SDMemoryCache.m

@@ -84,6 +84,9 @@ static void * SDMemoryCacheContext = &SDMemoryCacheContext;
 // `setObject:forKey:` just call this with 0 cost. Override this is enough
 - (void)setObject:(id)obj forKey:(id)key cost:(NSUInteger)g {
     [super setObject:obj forKey:key cost:g];
+    if (!self.config.shouldUseWeakMemoryCache) {
+        return;
+    }
     if (key && obj) {
         // Store weak cache
         LOCK(self.weakCacheLock);
@@ -94,6 +97,9 @@ static void * SDMemoryCacheContext = &SDMemoryCacheContext;
 
 - (id)objectForKey:(id)key {
     id obj = [super objectForKey:key];
+    if (!self.config.shouldUseWeakMemoryCache) {
+        return obj;
+    }
     if (key && !obj) {
         // Check weak cache
         LOCK(self.weakCacheLock);
@@ -113,6 +119,9 @@ static void * SDMemoryCacheContext = &SDMemoryCacheContext;
 
 - (void)removeObjectForKey:(id)key {
     [super removeObjectForKey:key];
+    if (!self.config.shouldUseWeakMemoryCache) {
+        return;
+    }
     if (key) {
         // Remove weak cache
         LOCK(self.weakCacheLock);
@@ -123,6 +132,9 @@ static void * SDMemoryCacheContext = &SDMemoryCacheContext;
 
 - (void)removeAllObjects {
     [super removeAllObjects];
+    if (!self.config.shouldUseWeakMemoryCache) {
+        return;
+    }
     // Manually remove should also remove weak cache
     LOCK(self.weakCacheLock);
     [self.weakCache removeAllObjects];