build: do not build mksnapshot and mkcodecache for --shared

To build mkcodecache and mksnapshot (they are executables),
we currently build libnode with unresolved symbols, then build
the two exectuables with src/node_snapshot_stub.cc and
src/node_code_cache_stub.cc. Each of them write a C++ file to
disk when being run. We then use the generated C++ files & libnode
(with unresolved symbols) to build the final Node executable.

However, if libnode itself is the final product, then we should
not build it with unresolved symbols.
nodejs#28897 added the two stubs
for the libnode target when the --shared configure option is used,
but it did not get rid of the actions to build and run mksnapshot
and mkcodecache for --shared, so I think to get it working we also
need a patch to make sure --shared imply --without-node-code-cache
and --without-node-snapshot, until we actually fix the TODO so that
mksnapshot and mkcodecache do not use the libnode that way.

Author: joyeecheung

configure.py

@@ -981,13 +981,13 @@ def configure_node(o):
   o['variables']['want_separate_host_toolset'] = int(cross_compiling)
 
   if not options.without_node_snapshot:
-    o['variables']['node_use_node_snapshot'] = b(not cross_compiling)
+    o['variables']['node_use_node_snapshot'] = b(not cross_compiling and not options.shared)
   else:
     o['variables']['node_use_node_snapshot'] = 'false'
 
   if not options.without_node_code_cache:
     # TODO(refack): fix this when implementing embedded code-cache when cross-compiling.
-    o['variables']['node_use_node_code_cache'] = b(not cross_compiling)
+    o['variables']['node_use_node_code_cache'] = b(not cross_compiling and not options.shared)
   else:
     o['variables']['node_use_node_code_cache'] = 'false'