[wasm] Remove the Float(32|64)SubMinusZero tests.

These tests became obsolete. They tested a requirement that has been
removed from the WebAssembly specification.

R=titzer@chromium.org, Balazs.Kilvady@imgtec.com

Review-Url: https://codereview.chromium.org/2284593002
Cr-Commit-Position: refs/heads/master@{#38938}

test/cctest/wasm/test-run-wasm.cc

@@ -605,46 +605,6 @@ WASM_EXEC_TEST(Float32Neg) {
   }
 }
 
-WASM_EXEC_TEST(Float32SubMinusZero) {
-  WasmRunner<float> r(execution_mode, MachineType::Float32());
-  BUILD(r, WASM_F32_SUB(WASM_F32(-0.0), WASM_GET_LOCAL(0)));
-
-  uint32_t sNanValue =
-      bit_cast<uint32_t>(std::numeric_limits<float>::signaling_NaN());
-  uint32_t qNanValue =
-      bit_cast<uint32_t>(std::numeric_limits<float>::quiet_NaN());
-  uint32_t payload = 0x00200000;
-
-  uint32_t expected = (qNanValue & 0xffc00000) | payload;
-  uint32_t operand = (sNanValue & 0xffc00000) | payload;
-  CHECK_EQ(expected, bit_cast<uint32_t>(r.Call(bit_cast<float>(operand))));
-
-  // Change the sign of the NaN.
-  expected |= 0x80000000;
-  operand |= 0x80000000;
-  CHECK_EQ(expected, bit_cast<uint32_t>(r.Call(bit_cast<float>(operand))));
-}
-
-WASM_EXEC_TEST(Float64SubMinusZero) {
-  WasmRunner<double> r(execution_mode, MachineType::Float64());
-  BUILD(r, WASM_F64_SUB(WASM_F64(-0.0), WASM_GET_LOCAL(0)));
-
-  uint64_t sNanValue =
-      bit_cast<uint64_t>(std::numeric_limits<double>::signaling_NaN());
-  uint64_t qNanValue =
-      bit_cast<uint64_t>(std::numeric_limits<double>::quiet_NaN());
-  uint64_t payload = 0x0000123456789abc;
-
-  uint64_t expected = (qNanValue & 0xfff8000000000000) | payload;
-  uint64_t operand = (sNanValue & 0xfff8000000000000) | payload;
-  CHECK_EQ(expected, bit_cast<uint64_t>(r.Call(bit_cast<double>(operand))));
-
-  // Change the sign of the NaN.
-  expected |= 0x8000000000000000;
-  operand |= 0x8000000000000000;
-  CHECK_EQ(expected, bit_cast<uint64_t>(r.Call(bit_cast<double>(operand))));
-}
-
 WASM_EXEC_TEST(Float64Neg) {
   WasmRunner<double> r(execution_mode, MachineType::Float64());
   BUILD(r, WASM_F64_NEG(WASM_GET_LOCAL(0)));