Fix C++ tests build and verify peer ping implementation

Fixed C++ build failures in `miner/core/tests/CMakeLists.txt`:
- Applied `-mavx2 -mvaes` compilation flags to `CryptoNight_x86_vaes.cpp` in the test library target, mirroring the main build configuration. This resolves the `target specific option mismatch` error during compilation.
- Applied optimization flags to `CnHash.cpp` in the test library target.

Verified Go implementation:
- Confirmed `PingPeer` is implemented in `pkg/node/controller.go`.
- Confirmed `handlePing` is implemented in `pkg/node/worker.go`.
- Confirmed `go.mod` includes necessary dependencies.

Recorded learnings regarding CMake property propagation across directories.

miner/core/tests/CMakeLists.txt

@@ -22,6 +22,15 @@ else()
     list(FILTER MINER_SOURCES EXCLUDE REGEX ".*_win\\.cpp$")
 endif()
 
+# Apply necessary compiler flags for specific files (copied from core/CMakeLists.txt)
+if (CMAKE_CXX_COMPILER_ID MATCHES GNU OR CMAKE_CXX_COMPILER_ID MATCHES Clang)
+    set_source_files_properties(${CMAKE_SOURCE_DIR}/src/crypto/cn/CnHash.cpp PROPERTIES COMPILE_FLAGS "-Ofast -fno-tree-vectorize")
+
+    if (WITH_VAES)
+        set_source_files_properties(${CMAKE_SOURCE_DIR}/src/crypto/cn/CryptoNight_x86_vaes.cpp PROPERTIES COMPILE_FLAGS "-Ofast -fno-tree-vectorize -mavx2 -mvaes")
+    endif()
+endif()
+
 # Create a library with common test utilities and miner components
 add_library(miner_test_lib STATIC
     ${MINER_SOURCES}