client.cleancall: Prevent foo() from being optimized away, which was observed with new toolchains. This is more a bandaid than a fix, and we should re-write this test into using clean assembler instead. Furthermore, adds a pragma to prevent loop unrolling that caused the test to break on such systems.
common.decode: On some systems, the monitor instruction is enabled and does not cause an UD fault. This change here keeps the eax address valid so the monitor instruction will not throw an GP exception.