src: restore context default IsCodeGenerationFromStringsAllowed value
Context's default IsCodeGenerationFromStringsAllowed value can be
changed by v8 flag --disallow-code-generation-from-strings
. Restore
the value at runtime when delegating the code generation validation to
node::ModifyCodeGenerationFromStrings
.
The context's settings are serialized in the snapshot. Reset the setting values to its default values before the serialization so that it can be correctly re-initialized after deserialization at runtime.