Add bangCall parsing to lsc test suite

Author: wcjohnson

src/plugins/safeCallExistential.js

@@ -65,7 +65,9 @@ export default function(parser) {
     if (this.hasPlugin("existentialExpression")) {
       return this.parseExistential(lhs, startPos, startLoc);
     } else {
-      this.unexpected(questionPos);
+      // Possibly a flow type assertion; unwind
+      this.state = state;
+      return [null, false];
     }
   };
 

test/fixtures/lightscript/options.json

@@ -3,7 +3,7 @@
   "alternatives": {
     "all": {
       "allPlugins": true,
-      "excludePlugins": ["existentialExpression", "safeCallExpression", "splatComprehension", "bangCall", "flippedImports", "whiteblockOnly"]
+      "excludePlugins": ["existentialExpression", "flippedImports", "whiteblockOnly"]
     }
   }
 }