VM: [Kernel] Add kernel::ConstantEvaluator support for string.length

tests/language/language_kernel.status

Index: tests/language/language_kernel.status
diff --git a/tests/language/language_kernel.status b/tests/language/language_kernel.status
index 36eb6df8e7f9895f08512e067694686eb209a29a..d491b7e6545ad5efaf12742c5890dd45c5d1a958 100644
--- a/tests/language/language_kernel.status
+++ b/tests/language/language_kernel.status
@@ -118,10 +118,9 @@ accessor_conflict_import_prefixed_test: RuntimeError
 accessor_conflict_import_test: RuntimeError
 assertion_test: RuntimeError
 bad_raw_string_negative_test: Fail
-cha_deopt1_test: RuntimeError
-cha_deopt2_test: RuntimeError
-cha_deopt3_test: RuntimeError
-compile_time_constant12_test: Crash
+cha_deopt1_test: RuntimeError  # Deferred Loading Issue 28335
+cha_deopt2_test: RuntimeError  # Deferred Loading Issue 28335
+cha_deopt3_test: RuntimeError  # Deferred Loading Issue 28335
 compile_time_constant_k_test/01: RuntimeError
 compile_time_constant_k_test/02: RuntimeError
 compile_time_constant_k_test/03: RuntimeError
@@ -256,7 +255,7 @@ library_env_test/has_no_io_support: RuntimeError
 list_literal4_test: RuntimeError
 malformed_test/none: RuntimeError
 map_literal3_test: RuntimeError
-map_literal4_test: RuntimeError
+map_literal4_test: RuntimeError  # Checked Mode Issue
 map_literal6_test: RuntimeError
 method_override_test: RuntimeError
 mixin_mixin2_test: RuntimeError
@@ -277,7 +276,7 @@ redirecting_constructor_initializer_test: RuntimeError
 regress_22443_test: RuntimeError  # Deferred Loading Issue 28335
 regress_23408_test: RuntimeError  # Deferred Loading Issue 28335
 regress_r24720_test: RuntimeError
-regress_28278_test: RuntimeError
+regress_28278_test: RuntimeError  # Mirrors Issue
 script1_negative_test: Fail
 script2_negative_test: Fail
 setter_no_getter_call_test/none: RuntimeError