tests: fix clang warnings

Change-Id: I5dddc85169d7ef515c99dd1ab824573cbc1b5f2b
test56: fix race condition

Change-Id: I42bfe2b150e92f760794b4a03e62859c8bd7a992
Remove support for call profiling

The entire infrastructure relied on an ACK feature, and as such, it
has been broken for years now, with no easy way to repair it.

Change-Id: I783c2a21276967af115a642199f31fef0f14a572
libsffs: make path names constant

And a few other related warning fixes.

Change-Id: I1a49b9ee04c2b1bf80bc943272f72ffd6de77ef6