Enable compiler optimizations and enforce x86-64-v2 on GCC/Clang (#9442)

* Testing LTO (#4)

* Testing LTO

* clang

* linux

* Added the rest of Blinkhawk's optimizations

* Unlikely asserts

* Removing LTO from Linux builds - GCC

* Removing LTO from Linux builds - Clang

.ci/scripts/linux/docker.sh

@@ -12,6 +12,7 @@ mkdir build || true && cd build
 cmake .. \
       -DBoost_USE_STATIC_LIBS=ON \
       -DCMAKE_BUILD_TYPE=Release \
+      -DCMAKE_CXX_FLAGS="-march=x86-64-v2" \
       -DCMAKE_CXX_COMPILER=/usr/lib/ccache/g++ \
       -DCMAKE_C_COMPILER=/usr/lib/ccache/gcc \
       -DCMAKE_INSTALL_PREFIX="/usr" \