build: move headers out of c++ src section

This commit moves a few header files that are listed among the C++
source files for consistency.

PR-URL: #24124
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Matheus Marchini <mat@mmarchini.me>

node.gyp

@@ -337,15 +337,12 @@
         'src/module_wrap.cc',
         'src/node.cc',
         'src/node_api.cc',
-        'src/node_api.h',
-        'src/node_api_types.h',
         'src/node_buffer.cc',
         'src/node_config.cc',
         'src/node_constants.cc',
         'src/node_contextify.cc',
         'src/node_domain.cc',
         'src/node_encoding.cc',
-        'src/node_errors.h',
         'src/node_errors.cc',
         'src/node_file.cc',
         'src/node_http2.cc',
@@ -404,10 +401,13 @@
         'src/js_stream.h',
         'src/module_wrap.h',
         'src/node.h',
+        'src/node_api.h',
+        'src/node_api_types.h',
         'src/node_buffer.h',
         'src/node_code_cache.h',
         'src/node_constants.h',
         'src/node_contextify.h',
+        'src/node_errors.h',
         'src/node_file.h',
         'src/node_http2.h',
         'src/node_http2_state.h',