Build gmock cleanly with clang -Wextra-semi and -Wextra-semi-stmt

Extends 56ef07a2 to take -Wc++98-compat-extra-semi
(https://reviews.llvm.org/D43162) and -Wextra-semi-stmt
(https://reviews.llvm.org/D52695) into account.

For https://crbug.com/926235.

PiperOrigin-RevId: 236643095