WAsm SIMD version of X32 FILL microkernel

PiperOrigin-RevId: 321631312
diff --git a/BUILD.bazel b/BUILD.bazel
index a077e46..de4039a 100644
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -788,6 +788,7 @@
     "src/f32-vunary/gen/vneg-wasmsimd-x8.c",
     "src/f32-vunary/gen/vsqr-wasmsimd-x4.c",
     "src/f32-vunary/gen/vsqr-wasmsimd-x8.c",
+    "src/x32-fill/wasmsimd.c",
     "src/x32-packx/x4-wasmsimd.c",
     "src/math/roundne-wasmsimd-addsub.c",
     "src/math/roundd-wasmsimd-addsub.c",