Add CMake installation rules (#2184)

Add installation rules for all the binary targets.

Targets are installed under `<CMAKE_INSTALL_PREFIX>/bin/<CONFIG>` where
`<CONFIG>` is `CMAKE_BUILD_TYPE` for single-config generators, e.g. Unix
Makefiles and Ninja, or the build configuration for multi-config
generators, e.g. Ninja Multi-Config and Visual Studio.

This creates the target `install` on Unix and `INSTALL` on Windows.

test_conformance/spirv_new/spirv_asm/CMakeLists.txt

@@ -500,3 +500,10 @@ add_custom_command(
     VERBATIM)
 
 add_custom_target(spirv_new_binaries DEPENDS ${assembled_spirv_binaries})
+
+include(GNUInstallDirs)
+
+install(DIRECTORY
+            ${CMAKE_CURRENT_BINARY_DIR}/../spirv_bin
+        DESTINATION
+            ${CMAKE_INSTALL_BINDIR}/$<CONFIG>)