When running in MSVC compatibility mode, previously no deprecated copy
operation warnings (enabled by -Wdeprecated-copy) were raised. This
restriction was already in place when the deprecated copy warning was
first introduced.
This patch removes said restriction so that deprecated copy warnings, if
enabled, are also raised in MSVC compatibility mode. The reasoning here
being that these warnings are still useful when running in MSVC
compatibility mode and also have to be semi-explicitly enabled in the
first place (using -Wdeprecated-copy, -Wdeprecated or -Wextra).
Differential Revision: https://reviews.llvm.org/D133354