remove type piracy from == defined in Compiler (JuliaLang#56541)

`Compiler.:(==)` is now identical to `Base.:(==)`, so the following `==`
methods defined in typelattice.jl are considered type piracy:
https://github.com/JuliaLang/julia/blob/1edc6f1b7752ed67059020ba7ce174dffa225954/Compiler/src/typelattice.jl#L194-L197

In fact, loading `Compiler` as a standard library with this code can
sometimes result in errors like the following:
```julia
julia> using Compiler

julia> Int == Core.Const(1)
ERROR: MethodError: ==(::Type{Int64}, ::Core.Const) is ambiguous.
...
```

Since these `==` definitions no longer seem necessary, this commit
simply removes them to resolve the issue.

@nanosoldier `runbenchmarks("inference", vs=":master")`

Author: aviatesk

src/typelattice.jl

@@ -191,11 +191,6 @@ struct NotFound end
 
 const NOT_FOUND = NotFound()
 
-const CompilerTypes = Union{Const, Conditional, MustAlias, NotFound, PartialStruct}
-==(x::CompilerTypes, y::CompilerTypes) = x === y
-==(x::Type, y::CompilerTypes) = false
-==(x::CompilerTypes, y::Type) = false
-
 #################
 # lattice logic #
 #################