Auto merge of #89343 - Mark-Simulacrum:no-args-queries, r=cjgillot

Refactor fingerprint reconstruction

This PR replaces can_reconstruct_query_key with fingerprint_style, which returns the style of the fingerprint for that query. This allows us to avoid trying to extract a DefId (or equivalent) from keys which *are* reconstructible because they're () but not as DefIds.

This is done with the goal of fixing -Zdump-dep-graph, which seems to have broken a while ago (I didn't try to bisect). Currently even on a `fn main() {}` file it'll ICE (you need to also pass -Zquery-dep-graph for it to work at all), and this patch indirectly fixes the cause of that ICE. This also adds a test for it continuing to work.

src/test/run-make/dep-graph/Makefile

@@ -0,0 +1,12 @@
+-include ../../run-make-fulldeps/tools.mk
+
+# ignore-cross-compile
+
+# Just verify that we successfully run and produce dep graphs when requested.
+
+all:
+	RUST_DEP_GRAPH=$(TMPDIR)/dep-graph $(RUSTC) \
+        -Cincremental=$(TMPDIR)/incr \
+        -Zquery-dep-graph -Zdump-dep-graph foo.rs
+	test -f $(TMPDIR)/dep-graph.txt
+	test -f $(TMPDIR)/dep-graph.dot

src/test/run-make/dep-graph/foo.rs

@@ -0,0 +1 @@
+fn main() {}