EventPipe container types optimizations. (#83251)

EventPipe container types optimizations. (#83251)

During work collecting regressions statistics for #78852 I did some profiling on performance tests included in native EventPipe tests, https://github.com/dotnet/runtime/blob/main/src/mono/mono/eventpipe/test. This commit implements a couple of optimizations in the EventPipe native container classes as well as Mono's EventPipe implementation improving performance in low level native EventPipe performance tests.

Commit also includes a number of new native EventPipe tests covering optimizations done in dn_vector_ptr_t.