[decompiler] clean up vector detection and add vector float product detection (#638)

* change

* recognize vector float product and update tests

test/decompiler/reference/engine/load/load-dgo_REF.gc

@@ -136,8 +136,7 @@
 (defun str-load-cancel ()
   (set! *load-str-lock* #f)
   (set! *que-str-lock* #t)
-  (let ((v0-0 0))
-   )
+  0
   (none)
   )
 
@@ -150,10 +149,8 @@
    (set! (-> cmd address) addr)
    (set! (-> cmd result) (load-msg-result done))
    )
-  (let ((v1-2 0))
-   )
-  (let ((v0-2 0))
-   )
+  0
+  0
   (none)
   )
 
@@ -165,8 +162,7 @@
    (charp<-string (-> cmd basename) name)
    (set! (-> cmd result) (load-msg-result error))
    )
-  (let ((v0-2 0))
-   )
+  0
   (none)
   )
 
@@ -185,8 +181,7 @@
     )
    )
   (set! *que-str-lock* #f)
-  (let ((v0-3 0))
-   )
+  0
   (none)
   )
 
@@ -199,10 +194,8 @@
    (charp<-string (&-> cmd basename 1) name)
    (set! (-> cmd result) (load-msg-result done))
    )
-  (let ((v1-3 0))
-   )
-  (let ((v0-2 0))
-   )
+  0
+  0
   (none)
   )
 
@@ -215,8 +208,7 @@
    (charp<-string (&-> cmd basename 1) name)
    (set! (-> cmd result) (load-msg-result error))
    )
-  (let ((v0-2 0))
-   )
+  0
   (none)
   )
 
@@ -230,8 +222,7 @@
     (call *play-str-rpc* (the-as uint 0) (the-as pointer 0) (the-as uint 0))
     )
    )
-  (let ((v0-2 0))
-   )
+  0
   (none)
   )
 
@@ -314,8 +305,7 @@
   (let ((cmd (add-element *load-dgo-rpc*)))
    (call *load-dgo-rpc* (the-as uint 2) cmd (the-as uint 32))
    )
-  (let ((v0-3 0))
-   )
+  0
   (none)
   )
 
@@ -413,7 +403,6 @@
    (set! (-> arg0 0) (the-as uint #xffffffff))
    (set! arg0 (&-> arg0 1))
    )
-  (let ((v0-0 0))
-   )
+  0
   (none)
   )

test/decompiler/reference/engine/load/loader-h_REF.gc

@@ -272,5 +272,4 @@
   )
 
 ;; failed to figure out what this is:
-(let ((v0-12 0))
-  )
+0

test/decompiler/reference/engine/load/ramdisk_REF.gc

@@ -95,11 +95,9 @@
 ;; INFO: Return type mismatch int vs none.
 (defun ramdisk-sync ()
   (sync *ramdisk-rpc* #t)
-  (let ((v0-1 0))
-   )
+  0
   (none)
   )
 
 ;; failed to figure out what this is:
-(let ((v0-7 0))
-  )
+0