wsl/libhsakmt: move system heap from device to thunk runtime

In multi-GPU, system heap space is shared between all GPUs, not belongs to
specific one GPU, so move it from wddm device (which presents a specific GPU)
to thunk runtime which has gloable view, can manage system heap for all GPUs.

Introduce a new va_Mgr instance to manage system heap, since local heap
and system heap both comply with SVM(Shared Virtual Memory), without
this new mgr, every allocation has to call KMD at least once (each GPU
needs a call) to allocate GPU VA, the new mgr manage the space itself,
no longer call KMD.

Reviewed-by: Flora Cui <flora.cui@amd.com>
Signed-off-by: tiancyin <tianci.yin@amd.com>

memory.cpp

@@ -547,7 +547,7 @@ HSAKMT_STATUS import_dmabuf_fd(int DMABufFd,
     struct stat st;
     fstat(DMABufFd, &st);
     uint64_t sz = st.st_size;
-    if (4096 <= sz && sz < dev->SystemHeapSize() && (sz & 0xfff) == 0) {
+    if (4096 <= sz && sz < dxg_runtime->SystemHeapSize() && (sz & 0xfff) == 0) {
       pr_debug("DMABufFd %d is sys mem fd(IPC signal), get size:%ld from it\n", DMABufFd, st.st_size);
       create_info.flags.sysmem_ipc_sig_importer = 1;        // set to 1 when backend is system memory
       create_info.size = st.st_size;