liblog: reset pid and uid cache after a vfork()

(cherry pick from commit ec4f5c776d2bde026e2a74128218924be7b3f46a)

Bionic getuid() and getpid() calls cache to reduce the need to
perform a syscall, and also reset their own cache after a vfork().
No more need for liblog to be performing this flawed cache operation.

Bug: 30085794
Change-Id: I70feed8bff0ddd919c2885a348ba67b14ddc0e0d
3 files changed
tree: 896fd30ab697ff3f2790830c5962399714ec3051
  1. liblog/
  2. logcat/
  3. logd/
  4. logwrapper/