scripts: tests: fix component_test_full_cmake_clang

Use the proper Clang C++ compiler to build C++ code otherwise the C
compiler will fail because std::cout() is unknown in
"cpp_dummy_build.cpp".

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/tests/scripts/components-configuration.sh b/tests/scripts/components-configuration.sh
index cc2cf06..5fd9ede 100644
--- a/tests/scripts/components-configuration.sh
+++ b/tests/scripts/components-configuration.sh
@@ -132,7 +132,8 @@
 component_test_full_cmake_clang () {
     msg "build: cmake, full config, clang" # ~ 50s
     scripts/config.py full
-    CC=clang CXX=clang cmake -D CMAKE_BUILD_TYPE:String=Release -D ENABLE_TESTING=On -D TEST_CPP=1 .
+    CC=clang CXX=clang++ cmake -D CMAKE_BUILD_TYPE:String=Release \
+                               -D ENABLE_TESTING=On -D TEST_CPP=1 .
     make
 
     msg "test: main suites (full config, clang)" # ~ 5s