MIPS: Drop clang version check for __builtin_isinf and __builtin_isnan
Cherry-pick from https://android-review.googlesource.com/#/c/123717/
Change-Id: I57e04e59d047fad89d8eea44748a57df8f31799f
Reviewed-on: https://chromium-review.googlesource.com/264970
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Tested-by: Ross McIlroy <rmcilroy@chromium.org>