[build] Update to Focal sysroot.

Our minimum supported version is Jammy, which Fuchsia doesn't have a CIPD package for, but at least we no longer need to use a different sysroot for different architectures.

Change-Id: I90f37797c2f2f79886df85d6b7ed9903270e8c2a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/433561
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>

DEPS

@@ -386,16 +386,6 @@ deps = {
   Var("dart_root") + "/third_party/pkg/web":
       Var("dart_git") + "web.git" + "@" + Var("web_rev"),
 
-  Var("dart_root") + "/buildtools/sysroot/linux": {
-      "packages": [
-          {
-              "package": "fuchsia/third_party/sysroot/linux",
-              "version": "git_revision:fa7a5a9710540f30ff98ae48b62f2cdf72ed2acd",
-          },
-      ],
-      "condition": "host_os == linux",
-      "dep_type": "cipd",
-  },
   Var("dart_root") + "/buildtools/sysroot/focal": {
       "packages": [
           {

build/config/compiler/BUILD.gn

@@ -414,13 +414,8 @@ config("compiler") {
     defines = [ "TOOLCHAIN_VERSION=${toolchain_cipd_version.instance_id}" ]
 
     if (is_linux) {
-      if (current_cpu == "riscv64") {
-        sysroot_stamp_file =
-            "//buildtools/sysroot/focal/.versions/sysroot.cipd_version"
-      } else {
-        sysroot_stamp_file =
-            "//buildtools/sysroot/linux/.versions/sysroot.cipd_version"
-      }
+      sysroot_stamp_file =
+          "//buildtools/sysroot/focal/.versions/sysroot.cipd_version"
       sysroot_cipd_version = read_file(sysroot_stamp_file, "json")
       defines += [ "SYSROOT_VERSION=${sysroot_cipd_version.instance_id}" ]
     }

build/config/sysroot.gni

@@ -37,12 +37,7 @@ if (is_linux) {
       assert(false)
     }
   } else if (dart_sysroot == "debian") {
-    if (current_cpu == "riscv64") {
-      target_sysroot = rebase_path("//buildtools/sysroot/focal", root_build_dir)
-    } else {
-      # Updating to focal would increase the required libc from 2.17 to 2.28.
-      target_sysroot = rebase_path("//buildtools/sysroot/linux", root_build_dir)
-    }
+    target_sysroot = rebase_path("//buildtools/sysroot/focal", root_build_dir)
   } else if (dart_sysroot != "") {
     print("There is no $dart_sysroot sysroot support")
     assert(false)