Fix Greentea test code

Mark mbed-os-tests-mbed_hal-common_tickers/time_cpu_cycles not in-lined.
Otherwise, time_cpu_cycles may be in-lined somewhere and takes different
CPU cycles on invocation.

TESTS/mbed_hal/common_tickers/main.cpp

@@ -52,6 +52,7 @@ unsigned int ticker_overflow_delta;
 
 /* Auxiliary function to count ticker ticks elapsed during execution of N cycles of empty while loop.
  * Parameter <step> is used to disable compiler optimisation. */
+MBED_NOINLINE
 uint32_t count_ticks(uint32_t cycles, uint32_t step)
 {
     register uint32_t reg_cycles = cycles;