mac: disable firefox importer tests on arm

These importer tests rely on loading some dylibs out of
//chrome/test/data/firefox3_nss_mac, which aren't yet (and may never)
be available for arm64.

Bug: 1121685
Change-Id: Ifb316784e3ffd851d3b507baa630f746695bdb29
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2375895Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#801757}

chrome/utility/importer/firefox_importer_unittest.cc

@@ -58,6 +58,9 @@ void ImportBookmarksFromVersion(base::StringPiece firefox_version,
 // TODO(jschuh): Disabled on Win64 build. http://crbug.com/179688
 #if defined(OS_WIN) && defined(ARCH_CPU_X86_64)
 #define MAYBE_NSS(x) DISABLED_##x
+#elif defined(OS_MAC) && defined(ARCH_CPU_ARM_FAMILY)
+// No NSS dylibs are available for arm64: https://crbug.com/1121685
+#define MAYBE_NSS(x) DISABLED_##x
 #else
 #define MAYBE_NSS(x) x
 #endif