Fix asset resolver url handling

Summary:
1. file:// may get prepended to an http:// source URL during dev mode, making an invalid URL
2. the logic to detect `isLoadedFromFileSystem()` should've checked for file:// protocol to not get confused by http:// URL

Reviewed By: zahanm

Differential Revision: D6307187

fbshipit-source-id: e7e7a41bf721dd0601b0c1877e278e1e435ef5e2

Author: fkgozali

Libraries/Image/AssetSourceResolver.js

@@ -73,7 +73,7 @@ class AssetSourceResolver {
   }
 
   isLoadedFromFileSystem(): boolean {
-    return !!this.jsbundleUrl;
+    return !!(this.jsbundleUrl && this.jsbundleUrl.startsWith('file://'));
   }
 
   canLoadFromEmbeddedBundledLocation(): boolean {

Libraries/Image/resolveAssetSource.js

@@ -43,7 +43,7 @@ function _coerceLocalScriptURL(scriptURL: ?string): ?string {
       return null;
     }
     scriptURL = scriptURL.substring(0, scriptURL.lastIndexOf('/') + 1);
-    if (!scriptURL.startsWith('file://')) {
+    if (!scriptURL.includes('://')) {
       // Add file protocol in case we have an absolute file path and not a URL.
       // This shouldn't really be necessary. scriptURL should be a URL.
       scriptURL = 'file://' + scriptURL;