Update emscripten config settings to conform to the official emscript…

…en toolchain.

Current Bazel config settings for Emscripten are specific to TensorFlow.js's custom Emscripten toolchain, but TFJS is switching to the official toolchain in [#4769](tensorflow/tfjs#4769). The official emscripten toolchain expects `crosstool_top` to be `//emscripten_toolchain:everything`.

PiperOrigin-RevId: 360787196

BUILD.bazel

@@ -7438,21 +7438,21 @@ config_setting(
 
 config_setting(
     name = "emscripten",
-    values = {"crosstool_top": "//toolchain:emscripten"},
+    values = {"crosstool_top": "//emscripten_toolchain:everything"},
 )
 
 config_setting(
     name = "emscripten_wasm",
     values = {
-        "crosstool_top": "//toolchain:emscripten",
+        "crosstool_top": "//emscripten_toolchain:everything",
         "cpu": "wasm",
     },
 )
 
 config_setting(
     name = "emscripten_wasmsimd",
     values = {
-        "crosstool_top": "//toolchain:emscripten",
+        "crosstool_top": "//emscripten_toolchain:everything",
         "cpu": "wasm",
         "copt": "-msimd128",
     },