Use CUDA virtual memory for pinned memory allocation. (#10850)

- Add a grow-only virtual memory allocator.
- Define a driver API wrapper. Split up the runtime API wrapper.

tests/cpp/data/test_ellpack_page_raw_format.cu

@@ -72,7 +72,7 @@ TEST_P(TestEllpackPageRawFormat, DiskIO) {
 }
 
 TEST_P(TestEllpackPageRawFormat, DiskIOHmm) {
-  if (common::SupportsPageableMem()) {
+  if (curt::SupportsPageableMem()) {
     EllpackMmapStreamPolicy<EllpackPage, EllpackFormatPolicy> policy{true};
     this->Run(&policy, this->GetParam());
   } else {