Move fxv8_unittests.{cpp,h} and fxgc_unittests.{cpp,h} to testing/

Otherwise files like xfa/fxfa/parser/cxfa_node_unittest.cpp can't
include fxgc_unittest.h, because currently fxgc_unittest.h is part
of a pdfium_unittest_source_set("unittests") clause, which doesn't
make it available.

This makes sense, in some sense, because these files don't contain
individual tests in themselves, but rather classes from which other
tests may inherit.

-- kill some blank lines.

Change-Id: I9c1e2bfccb30c541db0d7c3de29f2da2527f21ea
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/71870
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/testing/fxv8_unittest.cpp b/testing/fxv8_unittest.cpp
new file mode 100644
index 0000000..e9f9d5c
--- /dev/null
+++ b/testing/fxv8_unittest.cpp
@@ -0,0 +1,24 @@
+// Copyright 2020 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "testing/fxv8_unittest.h"
+
+#include "fxjs/cfx_v8.h"
+#include "v8/include/v8.h"
+
+void FXV8UnitTest::V8IsolateDeleter::operator()(v8::Isolate* ptr) const {
+  ptr->Dispose();
+}
+
+FXV8UnitTest::FXV8UnitTest() = default;
+
+FXV8UnitTest::~FXV8UnitTest() = default;
+
+void FXV8UnitTest::SetUp() {
+  array_buffer_allocator_ = std::make_unique<CFX_V8ArrayBufferAllocator>();
+
+  v8::Isolate::CreateParams params;
+  params.array_buffer_allocator = array_buffer_allocator_.get();
+  isolate_.reset(v8::Isolate::New(params));
+}