[arm64] Prevent the compiler to use fmadd/fmsub while compiling cctest.

This ensures that the generated code output will match the reference code output
and fixes some failures when running tests natively.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/1744493003

Cr-Commit-Position: refs/heads/master@{#34354}

test/cctest/cctest.gyp

@@ -293,7 +293,8 @@
             },
           },
         }],
-        ['v8_target_arch=="ppc" or v8_target_arch=="ppc64"', {
+        ['v8_target_arch=="ppc" or v8_target_arch=="ppc64" \
+          or v8_target_arch=="arm" or v8_target_arch=="arm64"', {
           # disable fmadd/fmsub so that expected results match generated code in
           # RunFloat64MulAndFloat64Add1 and friends.
           'cflags': ['-ffp-contract=off'],