Fix Xcode 12.5 analyze issue in Storage unit tests (#8211)

Author: paulb777

.swiftpm/xcode/xcshareddata/xcschemes/StorageUnit.xcscheme

@@ -5,6 +5,22 @@
    <BuildAction
       parallelizeBuildables = "YES"
       buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "NO"
+            buildForProfiling = "NO"
+            buildForArchiving = "NO"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "StorageUnit"
+               BuildableName = "StorageUnit"
+               BlueprintName = "StorageUnit"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
    </BuildAction>
    <TestAction
       buildConfiguration = "Debug"

FirebaseStorage/Tests/Unit/FIRStorageReferenceTests.m

@@ -193,7 +193,7 @@ - (void)testReferenceWithNilFileURLFailsWithCompletion {
   NSString *tempFilePath = [NSTemporaryDirectory() stringByAppendingPathComponent:@"temp.data"];
   FIRStorageReference *ref = [self.storage referenceWithPath:tempFilePath];
 
-  NSURL *dummyFileURL = nil;
+  NSURL *dummyFileURL = [NSURL URLWithString:@"bad-url"];
 
   XCTestExpectation *expectation = [self expectationWithDescription:@"completionExpectation"];