gn build: Only build the TSan runtime on 64-bit platforms.

TSan only supports 64-bit platforms.

Differential Revision: https://reviews.llvm.org/D104755

llvm/utils/gn/secondary/compiler-rt/lib/BUILD.gn

@@ -7,8 +7,10 @@ group("lib") {
     deps += [
       "//compiler-rt/lib/asan",
       "//compiler-rt/lib/builtins",
-      "//compiler-rt/lib/tsan",
       "//compiler-rt/lib/ubsan_minimal",
     ]
+    if (current_cpu == "x64" || current_cpu == "arm64") {
+      deps += [ "//compiler-rt/lib/tsan" ]
+    }
   }
 }