runtime/cgo: ignore missing Info.plist files on iOS

When running Go programs on Corellium virtual iPhones, the Info.plist
files might not exist. Ignore the error.

Updates #31722

Change-Id: Id2e315c09346b69dda9e10cf29fb5dba6743aac4
Reviewed-on: https://go-review.googlesource.com/c/go/+/174202
Run-TryBot: Elias Naur <mail@eliasnaur.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/runtime/cgo/gcc_darwin_arm.c

@@ -103,7 +103,7 @@ init_working_dir()
 	}
 	CFURLRef url_ref = CFBundleCopyResourceURL(bundle, CFSTR("Info"), CFSTR("plist"), NULL);
 	if (url_ref == NULL) {
-		fprintf(stderr, "runtime/cgo: no Info.plist URL\n");
+		// No Info.plist found. It can happen on Corellium virtual devices.
 		return;
 	}
 	CFStringRef url_str_ref = CFURLGetString(url_ref);

src/runtime/cgo/gcc_darwin_arm64.c

@@ -105,7 +105,7 @@ init_working_dir()
 	}
 	CFURLRef url_ref = CFBundleCopyResourceURL(bundle, CFSTR("Info"), CFSTR("plist"), NULL);
 	if (url_ref == NULL) {
-		fprintf(stderr, "runtime/cgo: no Info.plist URL\n");
+		// No Info.plist found. It can happen on Corellium virtual devices.
 		return;
 	}
 	CFStringRef url_str_ref = CFURLGetString(url_ref);