[Bugfix] Fix type code error for StringImm (#3050)

src/pass/lower_tvm_builtin.cc

@@ -251,6 +251,9 @@ class BuiltinLower : public IRMutator {
           stack_value_, static_cast<int>(arg_stack_begin + i - 1),
           intrinsic::kTVMValueContent, arg));
       int arg_tcode = api_type.code();
+      if (api_type.is_handle() && arg.as<StringImm>()) {
+        arg_tcode = kStr;
+      }
       if (IsArrayHandle(arg)) arg_tcode = kArrayHandle;
       prep_seq_.emplace_back(
           Store::make(stack_tcode_,

tests/python/unittest/test_runtime_measure.py

@@ -29,7 +29,6 @@ def test_min_repeat_ms():
     def my_debug(filename):
         """one call lasts for 100 ms and writes one character to a file"""
         time.sleep(0.1)
-        filename = ctypes.c_char_p(filename.value).value
         with open(filename, "a") as fout:
             fout.write("c")