[lldb][test] Skip all of JSONTransportTest.cpp file on Windows

We were cutting out the tests but leaving the utility functions,
leading to warnings like:
C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\llvm-project\lldb\unittests\Host\JSONTransportTest.cpp(65,6): warning: unused function 'operator==' [-Wunused-function]
C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\llvm-project\lldb\unittests\Host\JSONTransportTest.cpp(72,6): warning: unused function 'PrintTo' [-Wunused-function]

I've moved the ifndef to the start of the file to fix those.

Author: DavidSpickett

lldb/unittests/Host/JSONTransportTest.cpp

@@ -6,6 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+// Failing on Windows, see https://github.com/llvm/llvm-project/issues/153446.
+#ifndef _WIN32
+
 #include "lldb/Host/JSONTransport.h"
 #include "TestingSupport/Host/JSONTransportTestUtilities.h"
 #include "TestingSupport/Host/PipeTestUtilities.h"
@@ -377,8 +380,6 @@ class TransportBinderTest : public testing::Test {
 
 } // namespace
 
-// Failing on Windows, see https://github.com/llvm/llvm-project/issues/153446.
-#ifndef _WIN32
 using namespace test_protocol;
 
 TEST_F(HTTPDelimitedJSONTransportTest, MalformedRequests) {
@@ -813,4 +814,4 @@ TEST_F(TransportBinderTest, InBoundEventsVoidParams) {
   EXPECT_TRUE(called);
 }
 
-#endif
+#endif // ifndef _WIN32