kfdtest: Set XNACK mode according HSA_XNACK env setting

According env setting HSA_XNACK=1 or 0, set XNACK mode ON or OFF to run
KFDSVMRangeTest and KFDSVMEvictTest. If HSA_XNACK is not defined, use
system boot-time XNACK mode setting.

Restore to the original XNACK mode when test finished.

Change-Id: Ia896a1b0a90854646c8a79acca38a7d46098efde
Signed-off-by: Philip Yang <Philip.Yang@amd.com>

tests/kfdtest/src/KFDSVMEvictTest.cpp

@@ -35,6 +35,26 @@
 #define ALLOCATE_BUF_SIZE_MB    (64)
 #define ALLOCATE_RETRY_TIMES    (3)
 
+void KFDSVMEvictTest::SetUp() {
+    ROUTINE_START
+
+    KFDLocalMemoryTest::SetUp();
+
+    SVMSetXNACKMode();
+
+    ROUTINE_END
+}
+
+void KFDSVMEvictTest::TearDown() {
+    ROUTINE_START
+
+    SVMRestoreXNACKMode();
+
+    KFDLocalMemoryTest::TearDown();
+
+    ROUTINE_END
+}
+
 HSAint32 KFDSVMEvictTest::GetBufferCounter(HSAuint64 vramSize, HSAuint64 vramBufSize) {
     HSAuint64 vramBufSizeInPages = vramBufSize >> PAGE_SHIFT;
     HSAuint64 sysMemSize = GetSysMemSize();