EGL_KHR_fence_sync: Document 'pegl' prefix
EGL_KHR_fence_sync: Prefix global objects with 'g_'

Rename 'ctx' -> 'g_ctx' and 'dpy' -> 'g_dpy'. This fixes a bug in
init_context(). Pre-patch, init_context() clobbered the global ctx.
EGL_KHR_fence_sync: Fix names of early-written tests

All tests, except a few early-written ones, have names that follow the
form "${eglFuncName}_${description}". Fix the test names below to follow
that convention.

  create_with_invalid_display -> eglCreateSyncKHR_invalid_display
  create_with_invalid_attrib_list -> eglCreateSyncKHR_invalid_attrib_list
  create_without_current_context -> eglCreateSyncKHR_no_current_context
EGL_KHR_fence_sync: Let some funcs return piglit_result

Change init_display(), init_other_display(), and init_context() to
return piglit_result.

This patch makes progress towards running the multi-threaded test
without terminating early.
EGL_KHR_fence_sync: s/teardown/cleanup/

'cleanup' is shorter and easier to type.
EGL_KHR_fence_sync: Do better cleanup in init_context()

On error, unbind the context before queuing it for destruction.
EGL_KHR_fence_sync: Don't make GL calls if ctx is unbound

test_cleanup() made this mistake.
EGL_KHR_fence_sync: Remove a completed FINISHME
EGL_KHR_fence_sync: Fix comment typo s+/+.+
EGL_KHR_fence_sync: Document some spec excerpts as untested
EGL_KHR_fence_sync: Print thread id in log funcs
EGL_KHR_fence_sync: Add more error messages
EGL_KHR_fence_sync: Add helper check_sync_in_current_context()
EGL_KHR_fence_sync: Reduce false passes in multi-thread test

That is, test_eglCreateSyncKHR_with_display_bound_in_other_thread.
EGL_KHR_fence_sync: Simplify some gotos
EGL_KHR_fence_sync: Ensure ctx gets destroyed by unbinding it

eglDestroyContext only *queues* contexts destruction. They get
destroyed when they are no longer bound.
EGL_KHR_fence_sync: Use consistent goto label, s/done/cleanup/

Only one test used 'done' instead of 'cleanup'.
EGL_KHR_fence_sync: Return real pointer from thread2

All the casting between void** and enum piglit_result makes me
uncomfortable. Let's just malloc a piglit_result and return a real
pointer.
EGL_KHR_fence_sync: Initialize piglit_dispatch to ES2

Otherwise, the GL funcs all fail.
EGL_KHR_fence_sync: Run all subtests if cmdline selects none