Cleanup: Remove ppapi_internal.gyp from gyp_remaining target.
It is already done.
BUG=
461019
R=dpranke@chromium.org
CQ_EXTRA_TRYBOTS=tryserver.chromium.linux:android_chromium_gn_compile_dbg,android_chromium_gn_compile_rel;tryserver.chromium.win:win8_chromium_gn_rel,win8_chromium_gn_dbg;tryserver.chromium.mac:mac_chromium_gn_rel,mac_chromium_gn_dbg
Committed:
https://crrev.com/79ef072dd9082a432308e55a4adc93848df3449d
Cr-Commit-Position: refs/heads/master@{#323884}