Fix whitespace in a test

Author: DougGregor

validation-test/compiler_crashers_2_fixed/0133-rdar35832679.swift

@@ -1,8 +1,8 @@
 // RUN: %target-swift-frontend %s -emit-ir -o -
 
 func f() {
-		enum NotAnError: Swift.Error {
-			case nope(length: Int)
-		}
+  enum NotAnError: Swift.Error {
+    case nope(length: Int)
+  }
 }