fix some crashy behavior of invoke with builtins (#59451)

builtins have empty method tables so `invoke` will segfault or otherwise
crash (see some tests). this PR attempts to fix that

(cherry picked from commit 1811564)

Author: adienes

src/gf.c

@@ -150,7 +150,7 @@ static int speccache_eq(size_t idx, const void *ty, jl_value_t *data, uint_t hv)
 // get or create the MethodInstance for a specialization
 static jl_method_instance_t *jl_specializations_get_linfo_(jl_method_t *m JL_PROPAGATES_ROOT, jl_value_t *type, jl_svec_t *sparams, jl_method_instance_t *mi_insert)
 {
-    if (m->sig == (jl_value_t*)jl_anytuple_type && jl_atomic_load_relaxed(&m->unspecialized) != NULL && m != jl_opaque_closure_method && !m->is_for_opaque_closure)
+    if (m->source == NULL && m->generator == NULL && jl_atomic_load_relaxed(&m->unspecialized) != NULL && m != jl_opaque_closure_method && !m->is_for_opaque_closure)
         return jl_atomic_load_relaxed(&m->unspecialized); // handle builtin methods
     jl_value_t *ut = jl_is_unionall(type) ? jl_unwrap_unionall(type) : type;
     JL_TYPECHK(specializations, datatype, ut);

test/core.jl

@@ -2816,6 +2816,14 @@ const T24460 = Tuple{T,T} where T
 g24460() = invoke(f24460, T24460, 1, 2)
 @test @inferred(g24460()) === 2.0
 
+@testset "invoke with builtins" begin
+    @test invoke(getfield, Tuple{Any, Symbol}, (a = 42,), :a) == 42
+    @test invoke(setfield!, Tuple{Any, Symbol, Any},  Base.RefValue(1), :x, 2) == 2
+    @test invoke(isdefined, Tuple{Any, Symbol}, (a = 1,), :a) == true
+    @test invoke(isdefined, Tuple{Any, Symbol}, (a = 1,), :b) == false
+    @test invoke(invoke, Tuple{Any, Type, Vararg}, sin, Tuple{Real}, 0) == 0.0
+end
+
 # issue #30679
 @noinline function f30679(::DataType)
     b = IOBuffer()