Updated context management logic:

1) hipSetDevice sets a flag so that next call to hipCtxGetCurrent returns primary context on current device
2) hipCtxGetCurrent returns primary context on current device if TLS context stack is empty
3) hipCtxPopCurrent falls back to primary context on current device as default
4) hipCtxPushCurrent, hipCtxSetCurrent and hipCtxCreate reset the flag set in hipSetDevice


[ROCm/hip commit: 3e84cf4aba]

projects/hip/src/hip_device.cpp

@@ -146,6 +146,7 @@ hipError_t hipSetDevice(int deviceId)
         return ihipLogStatus(hipErrorInvalidDevice);
     } else {
         ihipSetTlsDefaultCtx(ihipGetPrimaryCtx(deviceId));
+        tls_getPrimaryCtx = true;
         return ihipLogStatus(hipSuccess);
     }
 }