THRIFT-4914: Fix name redeclaration bug in compiled go code

Client: go

This fixes the bug reported in
https://github.com/apache/thrift/pull/2315#discussion_r577919697.
diff --git a/test/ThriftTest.thrift b/test/ThriftTest.thrift
index ac49aee..c88187c 100644
--- a/test/ThriftTest.thrift
+++ b/test/ThriftTest.thrift
@@ -411,3 +411,17 @@
 struct OptionalSetDefaultTest {
   1: optional set<string> with_default = [ "test" ]
 }
+
+service ConflictingNamesTest {
+  /**
+   * Use some names that could conflict with the compiler code as args
+   * to make sure that the compiler handled them correctly.
+   */
+  void testNameConflicts(
+    // 1: string args,   // args is already a reserved keyword in thrift compiler
+    // 2: string result, // result will cause problems in compiled netstd code
+    3: string meta,
+    4: string r,
+    5: string err,
+  )
+}