n-api: remove unnecessary try-catch bracket from certain APIs

These APIs do not need a try-catch around their body, because no
exceptions are thrown in their implementation:
- `napi_is_array()`
- `napi_get_value_string_latin1()`
- `napi_get_value_string_utf8()`
- `napi_get_value_string_utf16()`
- `napi_get_value_external()`
- `napi_is_buffer()`
- `napi_is_arraybuffer()`
- `napi_get_arraybuffer_info()`
- `napi_is_typedarray()`
- `napi_get_typedarray_info()`

Fixes: https://github.com/nodejs/abi-stable-node/issues/238
PR-URL: https://github.com/nodejs/node/pull/12705


Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Jason Ginchereau <jasongin@microsoft.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>