Adding support for enum class in RTC_CHECK and RTC_LOG.

Enum class types are by design not convertible to arithmetic types.
As a result they are currently not supported in RTC_CHECK and RTC_LOG.
The current workaround was to use something like RTC_CHECK(v1 == v2)
instead of RTC_CHECK_EQ(v1, v2).
This change adds support for any enum class type by converting it to the
underlying type.

Bug: webrtc:10418
Change-Id: I59e6608e6a97a4cc007c903f8e021a58d4c49ff8
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/128202
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Amit Hilbuch <amithi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27166}