[OE-core] v2: valgrind upgrade to 3.14

[Randy MacLeod]

v2:

Remove unused patch that was dropped from recipe.
Guard against __GLIBC_PREREQ for musl libc

I've tested the enable-lto optimization and it's costly
at build time and doesn't work immediately so I think it
should be implemented as a PACKAGECONFIG post-ga.
It's also not the default configuration for valgrind-3.14
leaving it off by default seems reasonable.

As stated elsewhere the ptest results are ~52% so that's
better than with 3.13 but still not where are aiming so
we'll have to continue to work on it.