wsl/hsakmt: Introduce WSL_CHECK_AVAIL_SYSRAM environment variable

By default, this variable is 0. Set it to 1 to compare available
system memory with the requested amount before allocation. It helps
identify system hangs caused by excessive memory allocation.

Signed-off-by: lyndonli <Lyndon.Li@amd.com>
Reviewed-by: Flora Cui <flora.cui@amd.com>
Part-of: <http://10.67.69.192/wsl/libhsakmt/-/merge_requests/32>

globals.cpp

@@ -47,5 +47,7 @@ int zfb_support;
 int vendor_packet_support;
 /* enable vendor packet in hsa-runtime*/
 int enable_vendor_packet;
+/* check available system memory before allocation */
+bool check_avail_sysram = false;
 
 size_t max_single_alloc_size = 0;