Auto merge of #79106 - tmiasko:inline-hint, r=nagisa,eddyb

Auto merge of #79106 - tmiasko:inline-hint, r=nagisa,eddyb

Fix setting inline hint based on `InstanceDef::requires_inline`

For instances where `InstanceDef::requires_inline` is true, an attempt
is made to set an inline hint though a call to the `inline` function.
The attempt is ineffective, since all attributes will be usually removed
by the second call.

Fix the issue by applying the attributes only once, with user provided
attributes having a priority when provided.

Closes #79108.