Remove heaps from core Cranelift, push them into cranelift-wasm (#5386)

* cranelift-wasm: translate Wasm loads into lower-level CLIF operations

Rather than using `heap_{load,store,addr}`.

* cranelift: Remove the `heap_{addr,load,store}` instructions

These are now legalized in the `cranelift-wasm` frontend.

* cranelift: Remove the `ir::Heap` entity from CLIF

* Port basic memory operation tests to .wat filetests

* Remove test for verifying CLIF heaps

* Remove `heap_addr` from replace_branching_instructions_and_cfg_predecessors.clif test

* Remove `heap_addr` from readonly.clif test

* Remove `heap_addr` from `table_addr.clif` test

* Remove `heap_addr` from the simd-fvpromote_low.clif test

* Remove `heap_addr` from simd-fvdemote.clif test

* Remove `heap_addr` from the load-op-store.clif test

* Remove the CLIF heap runtest

* Remove `heap_addr` from the global_value.clif test

* Remove `heap_addr` from fpromote.clif runtests

* Remove `heap_addr` from fdemote.clif runtests

* Remove `heap_addr` from memory.clif parser test

* Remove `heap_addr` from reject_load_readonly.clif test

* Remove `heap_addr` from reject_load_notrap.clif test

* Remove `heap_addr` from load_readonly_notrap.clif test

* Remove `static-heap-without-guard-pages.clif` test

Will be subsumed when we port `make-heap-load-store-tests.sh` to generating
`.wat` tests.

* Remove `static-heap-with-guard-pages.clif` test

Will be subsumed when we port `make-heap-load-store-tests.sh` over to `.wat`
tests.

* Remove more heap tests

These will be subsumed by porting `make-heap-load-store-tests.sh` over to `.wat`
tests.

* Remove `heap_addr` from `simple-alias.clif` test

* Remove `heap_addr` from partial-redundancy.clif test

* Remove `heap_addr` from multiple-blocks.clif test

* Remove `heap_addr` from fence.clif test

* Remove `heap_addr` from extends.clif test

* Remove runtests that rely on heaps

Heaps are not a thing in CLIF or the interpreter anymore

* Add generated load/store `.wat` tests

* Enable memory-related wasm features in `.wat` tests

* Remove CLIF heap from fcmp-mem-bug.clif test

* Add a mode for compiling `.wat` all the way to assembly in filetests

* Also generate WAT to assembly tests in `make-load-store-tests.sh`

* cargo fmt

* Reinstate `f{de,pro}mote.clif` tests without the heap bits

* Remove undefined doc link

* Remove outdated SVG and dot file from docs

* Add docs about `None` returns for base address computation helpers

* Factor out `env.heap_access_spectre_mitigation()` to a local

* Expand docs for `FuncEnvironment::heaps` trait method

* Restore f{de,pro}mote+load clif runtests with stack memory

cranelift/frontend/src/frontend.rs

@@ -8,10 +8,10 @@ use cranelift_codegen::ir;
 use cranelift_codegen::ir::condcodes::IntCC;
 use cranelift_codegen::ir::{
     types, AbiParam, Block, DataFlowGraph, DynamicStackSlot, DynamicStackSlotData, ExtFuncData,
-    ExternalName, FuncRef, Function, GlobalValue, GlobalValueData, Heap, HeapData, Inst,
-    InstBuilder, InstBuilderBase, InstructionData, JumpTable, JumpTableData, LibCall, MemFlags,
-    RelSourceLoc, SigRef, Signature, StackSlot, StackSlotData, Type, Value, ValueLabel,
-    ValueLabelAssignments, ValueLabelStart,
+    ExternalName, FuncRef, Function, GlobalValue, GlobalValueData, Inst, InstBuilder,
+    InstBuilderBase, InstructionData, JumpTable, JumpTableData, LibCall, MemFlags, RelSourceLoc,
+    SigRef, Signature, StackSlot, StackSlotData, Type, Value, ValueLabel, ValueLabelAssignments,
+    ValueLabelStart,
 };
 use cranelift_codegen::isa::TargetFrontendConfig;
 use cranelift_codegen::packed_option::PackedOption;
@@ -512,11 +512,6 @@ impl<'a> FunctionBuilder<'a> {
         self.func.create_global_value(data)
     }
 
-    /// Declares a heap accessible to the function.
-    pub fn create_heap(&mut self, data: HeapData) -> Heap {
-        self.func.create_heap(data)
-    }
-
     /// Returns an object with the [`InstBuilder`](cranelift_codegen::ir::InstBuilder)
     /// trait that allows to conveniently append an instruction to the current `Block` being built.
     pub fn ins<'short>(&'short mut self) -> FuncInstBuilder<'short, 'a> {