build: add pgo specific variables to common.gypi

Refs: #22772 (comment)

PR-URL: #23102
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

common.gypi

@@ -9,6 +9,8 @@
     'library%': 'static_library',     # allow override to 'shared_library' for DLL/.so builds
     'component%': 'static_library',   # NB. these names match with what V8 expects
     'msvs_multi_core_compile': '0',   # we do enable multicore compiles, but not using the V8 way
+    'enable_pgo_generate%': '0',
+    'enable_pgo_use%': '0',
     'python%': 'python',
 
     'node_shared%': 'false',