Fix profiling when number of code sections decrease
Fix profiling when number of code sections decrease

Currently, the GPU code section profiling works only if the number of
profiled code sections does not decrease from one frame to the next. If
so, a NP-exception is thrown in Profiling.frame() -> l:179 String name =
section.name; as sections are set to null in RT.stringMarker(String) ->
l:1215 ctx.codeSectionTimes.set(i, null); replacing this line with
ctx.codeSectionTimes.remove(i); solves the issue.
LWJGLX/debug