[StackIR] Run StackIR during binary writing and not as a pass (#6568)

Previously we had passes --generate-stack-ir, --optimize-stack-ir, --print-stack-ir
that could be run like any other passes. After generating StackIR it was stashed on
the function and invalidated if we modified BinaryenIR. If it wasn't invalidated then
it was used during binary writing. This PR switches things so that we optionally
generate, optimize, and print StackIR only during binary writing. It also removes
all traces of StackIR from wasm.h - after this, StackIR is a feature of binary writing
(and printing) logic only.

This is almost NFC, but there are some minor noticeable differences:

1.  We no longer print has StackIR in the text format when we see it is there. It
    will not be there during normal printing, as it is only present during binary writing.
    (but --print-stack-ir still works as before; as mentioned above it runs during writing).
2.  --generate/optimize/print-stack-ir change from being passes to being flags that
    control that behavior instead. As passes, their order on the commandline mattered,
    while now it does not, and they only "globally" affect things during writing.
3.  The C API changes slightly, as there is no need to pass it an option "optimize" to
    the StackIR APIs. Whether we optimize is handled by --optimize-stack-ir which is
    set like other optimization flags on the PassOptions object, so we don't need the
    old option to those C APIs.

The main benefit here is simplifying the code, so we don't need to think about
StackIR in more places than just binary writing. That may also allow future
improvements to our usage of StackIR.

1 files changed, 11 insertions, 20 deletions

diff --git a/test/passes/O1_print-stack-ir.txt b/test/passes/O1_print-stack-ir.txt
index 0a64713d3..d6cececfc 100644
--- a/test/passes/O1_print-stack-ir.txt
+++ b/test/passes/O1_print-stack-ir.txt
@@ -28,25 +28,16 @@
  (type $0 (func (param i32) (result i32)))
  (export "stacky-help" (func $stacky-help))
  (func $stacky-help (param $0 i32) (result i32)
-  (i32.add
-   (call $stacky-help
-    (i32.const 0)
-   )
-   (block (result i32)
-    (local.set $0
-     (call $stacky-help
-      (i32.const 1)
-     )
-    )
-    (drop
-     (call $stacky-help
-      (i32.const 2)
-     )
-    )
-    (i32.eqz
-     (local.get $0)
-    )
-   )
-  )
+  i32.const 0
+  call $stacky-help
+  i32.const 1
+  call $stacky-help
+  local.set $0
+  i32.const 2
+  call $stacky-help
+  drop
+  local.get $0
+  i32.eqz
+  i32.add
  )
 )