When cross compiling inspector with GYP on MIPS and ARM, there are three
rules that generate the same file both host toolset and target toolset.
This causes problems because of rule duplication; depending on
compilation configuration this can cause warning or error.
We fix this by disabling the host rule and using target rule for all
depending rules.

BUG=v8:6176

Review-Url: https://codereview.chromium.org/2819283005
Cr-Commit-Position: refs/heads/master@{#44741}