WIP Add MIR argument for #[track_caller] (RFC 2091 3/N)

[anp]

Making this work requires making core::panic::Location a lang item, which is the first commit on this branch (prior are from the depended-on PR).

Depends on: #65182
Tracking issue: #47809
RFC text

TODO:

• add a location parameter to MIR of #[track_caller] in rustc_mir::build (reference existing implicit arguments work if needed)
• fix ty::Instance::fn_sig to contain the new type
  • note to self: check on by-val vs. by-ref for this arg used &'static per @eddyb
• add a "dummy" location parameter to calls from ReifyShim (see other shims for generating things in shims, ask @eddyb if fighting consteval)
• pass the "correct" location parameter to the function in all calls to ty::Instance::resolve
• wire up intrinsic::caller_location in MIR construction (reference move_val_init intrinsic)
• test it can't be called from non-caller-tracked functions (reference other intrinsics for how to type-check)
• make sure MIR inlining uses resolve, "change the ty::Instance::resolve callsite there"
• test that directly nested #[track_caller]s pass the same callsite
• test that indirectly nested #[track_caller]s pass distinct callsites
• check that all rfc-2091 tests are un-ice'd