Add CoreOption flag to "-coverage" option to make it available for clang-cl

[marco-c]

Summary

The -coverage option is not a CoreOption, so it is not available to clang-cl.
This patch adds the CoreOption flag to "-coverage" to allow it to be used with clang-cl.

[rnk]

lgtm

include/clang/Driver/Options.td

 def client__name : JoinedOrSeparate<["-"], "client_name">;
 def combine : Flag<["-", "--"], "combine">, Flags<[DriverOption, Unsupported]>;
 def compatibility__version : JoinedOrSeparate<["-"], "compatibility_version">;
-def coverage : Flag<["-", "--"], "coverage">;
+def coverage : Flag<["-", "--"], "coverage">, Flags<[CoreOption]>;
 def cpp_precomp : Flag<["-"], "cpp-precomp">, Group<clang_ignored_f_Group>;
 def current__version : JoinedOrSeparate<["-"], "current_version">;
 def cxx_isystem : JoinedOrSeparate<["-"], "cxx-isystem">, Group<clang_i_Group>,

test/Driver/coverage.c

+// Test coverage flag.
+//
+// RUN: %clang_cl -### -coverage %s -o foo/bar.o 2>&1 | FileCheck -check-prefix=CLANG-CL-COVERAGE %s
+// CLANG-CL-COVERAGE-NOT: error:
+// CLANG-CL-COVERAGE-NOT: warning:
+// CLANG-CL-COVERAGE-NOT: argument unused
+// CLANG-CL-COVERAGE-NOT: unknown argument