Disable libbacktrace enabled test on X86 platforms. (#523)

* Disable libbacktrace enabled test on X86 platforms.

* Fix mistype.

* Use macos-12 workers from now.

.github/workflows/ci.yml

@@ -34,7 +34,7 @@ jobs:
             shell: bash
           - target:
               os: macos
-            builder: macos-11
+            builder: macos-12
             shell: bash
           - target:
               os: windows

chronos.nimble

@@ -20,6 +20,7 @@ let nimc = getEnv("NIMC", "nim") # Which nim compiler to use
 let lang = getEnv("NIMLANG", "c") # Which backend (c/cpp/js)
 let flags = getEnv("NIMFLAGS", "") # Extra flags for the compiler
 let verbose = getEnv("V", "") notin ["", "0"]
+let platform = getEnv("PLATFORM", "")
 let testArguments =
   when defined(windows):
     [
@@ -60,6 +61,7 @@ task test, "Run all tests":
     run args, "tests/testall"
 
 task test_libbacktrace, "test with libbacktrace":
+  if platform != "x86":
     let allArgs = @[
       "-d:release --debugger:native -d:chronosStackTrace -d:nimStackTraceOverride --import:libbacktrace",
     ]