Enabling all DTrace fbt probes (fbt::: {}) hangs on the system on ARM platforms

[graeme.jenkinson_cl.cam.ac.uk]

Summary

Enabling all DTrace fbt probes fbt::: {} results in the system hanging on ARM platforms.

Fixed by calling fbt_excluded() to exclude common functions and then excluded ARM specific functions (undefined instruction and nanouptime). Excluding nanouptime means that this function can't be traced.

Test Plan

The fix was tested by running the following DTrace scripts:

fbt:::a*: { trace(probefunc); }
...
fbt:::z*: { trace(probefunc); }

fbt::: { trace(probefunc); }

[andrew]

Can you rebase this on top of rS309785?