Remove apparently unused _runBlock: method

Reviewed By: nicklockwood

Differential Revision: D3088409

fb-gh-sync-id: 279ce18f2a336819dbdc54087b1b7e203fbecac2
shipit-source-id: 279ce18f2a336819dbdc54087b1b7e203fbecac2

React/Executors/RCTJSCExecutor.m

@@ -594,11 +594,6 @@ static void RCTInstallJSCProfiler(RCTBridge *bridge, JSContextRef context)
           waitUntilDone:NO];
 }
 
-- (void)_runBlock:(dispatch_block_t)block
-{
-  block();
-}
-
 - (void)injectJSONText:(NSString *)script
    asGlobalObjectNamed:(NSString *)objectName
               callback:(RCTJavaScriptCompleteBlock)onComplete