Remove Emscripten support

test/CodeGen/JS/simd-misc.ll

-; RUN: llc < %s | FileCheck %s
-
-target datalayout = "e-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-p:32:32:32-v128:32:128-n32-S128"
-target triple = "asmjs-unknown-emscripten"
-
-declare <4 x float> @emscripten_float32x4_reciprocalApproximation(<4 x float>)
-declare <4 x float> @emscripten_float32x4_reciprocalSqrtApproximation(<4 x float>)
-
-; CHECK: function _test_rcp($a) {
-; CHECK: $a = SIMD_float32x4_check($a);
-; CHECK: SIMD_float32x4_reciprocalApproximation
-; CHECK:}
-define <4 x float> @test_rcp(<4 x float> %a) {
-    %c = call <4 x float> @emscripten_float32x4_reciprocalApproximation(<4 x float> %a)
-    ret <4 x float> %c
-}
-
-; CHECK: function _test_rsqrt($a) {
-; CHECK: $a = SIMD_float32x4_check($a);
-; CHECK: SIMD_float32x4_reciprocalSqrtApproximation
-; CHECK:}
-define <4 x float> @test_rsqrt(<4 x float> %a) {
-    %c = call <4 x float> @emscripten_float32x4_reciprocalSqrtApproximation(<4 x float> %a)
-    ret <4 x float> %c
-}