Fix duplicated message about missing IntelAmplifier

the message about non accessible IntelAmplifier should be printed once, but it was printed every time the toolchain was invoked... because we should have used message(STATUS ...) instead of message(INFO ...).

The point is that status messages are suppressed in the test builds that CMake runs to discover compiler features, so they are printed only for the first invocation of the toolchain. INFO is not a supported message level in CMake (see doc of message() command).