MIPS[64]: Skip float-constant-folding tests

qNaN and sNaN values have different binary representation on MIPS
compared to ARM/x86 architectures. We are skipping these tests because
we can't provide specific NaNs encodings from ARM/x86 architectures.

BUG=

Review-Url: https://codereview.chromium.org/2702213003
Cr-Commit-Position: refs/heads/master@{#43327}

test/mjsunit/mjsunit.status

@@ -418,6 +418,13 @@
   'array-functions-prototype-misc': [PASS, NO_VARIANTS],
 }],  # 'arch == mipsel or arch == mips or arch == mips64el or arch == mips64'
 
+##############################################################################
+['arch == mipsel or arch == mips or arch == mips64el or arch == mips64', {
+  # These tests fail because qNaN and sNaN values are encoded differently on
+  # MIPS and ARM/x86 architectures
+  'wasm/float-constant-folding': [SKIP],
+}],
+
 ##############################################################################
 ['arch == mipsel or arch == mips', {