switch custom target JSON test to a less exotic target

src/tools/miri/ci/ci.sh

@@ -159,8 +159,7 @@ case $HOST_TARGET in
     TEST_TARGET=wasm32-unknown-unknown run_tests_minimal no_std empty_main wasm # this target doesn't really have std
     TEST_TARGET=thumbv7em-none-eabihf  run_tests_minimal no_std
     # Custom target JSON file
-    # FIXME: disabled due to <https://github.com/rust-lang/rust/issues/130818>.
-    #TEST_TARGET=tests/avr.json MIRI_NO_STD=1 run_tests_minimal no_std
+    TEST_TARGET=tests/x86_64-unknown-kernel.json MIRI_NO_STD=1 run_tests_minimal no_std
     ;;
   i686-pc-windows-msvc)
     # Host

src/tools/miri/tests/avr.json

@@ -1,25 +0,0 @@
-{
-  "arch": "avr",
-  "cpu": "atmega328p",
-  "data-layout": "e-P1-p:16:8-i8:8-i16:8-i32:8-i64:8-f32:8-f64:8-n8-a:8",
-  "env": "",
-  "executables": true,
-  "linker": "avr-gcc",
-  "linker-flavor": "gcc",
-  "linker-is-gnu": true,
-  "llvm-target": "avr-unknown-unknown",
-  "os": "unknown",
-  "position-independent-executables": false,
-  "exe-suffix": ".elf",
-  "eh-frame-header": false,
-  "pre-link-args": {
-    "gcc": ["-mmcu=atmega328p"]
-  },
-  "late-link-args": {
-    "gcc": ["-lgcc"]
-  },
-  "target-c-int-width": "16",
-  "target-endian": "little",
-  "target-pointer-width": "16",
-  "vendor": "unknown"
-}

src/tools/miri/tests/x86_64-unknown-kernel.json

@@ -0,0 +1,24 @@
+{
+  "llvm-target": "x86_64-unknown-none",
+  "target-endian": "little",
+  "target-pointer-width": "64",
+  "target-c-int-width": "32",
+  "data-layout": "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128",
+  "arch": "x86_64",
+  "os": "none",
+  "env": "",
+  "vendor": "unknown",
+  "linker": "rust-lld",
+  "linker-flavor": "gnu-lld",
+  "features": "-mmx,-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2,+soft-float",
+  "dynamic-linking": false,
+  "executables": true,
+  "relocation-model": "static",
+  "code-model": "kernel",
+  "disable-redzone": true,
+  "frame-pointer": "always",
+  "exe-suffix": "",
+  "has-rpath": false,
+  "no-default-libraries": true,
+  "position-independent-executables": false
+}