Fix #14396 (#14793)

* Correct Left-To-Right evaluation of proc args
* Fix CPP backend
* Add testcase
* closes #14396
* closes #14345
* Improve test and optimize
* Improve testcase and optimize literals
* Fix bug
* Expand testcase and use DFA to optimize
* Turn genParams into proc
* Turn withTmpIfNeeded into a proc
* Cleanup
* Fix crash
* Better analysis
* Cleanup
* Trailing newline..
* Fix build
* Tiny cleanup

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>

tests/ccgbugs/targ_lefttoright.nim

@@ -0,0 +1,70 @@
+discard """
+  nimout: '''1,2
+2,3
+2,2
+1,2
+1,2
+2,2
+1,2
+'''
+  output: '''1,2
+2,3
+1,2
+2,2
+1,2
+1,2
+2,2
+1,2
+'''
+"""
+
+template test =
+  proc say(a, b: int) =
+    echo a,",",b
+
+  var a = 1
+  say a, (a += 1; a) #1,2
+
+  var b = 1
+  say (b += 1; b), (b += 1; b) #2,3
+
+  type C = object {.byRef.}
+    i: int
+
+  proc say(a, b: C) =
+    echo a.i,",",b.i
+
+  proc `+=`(x: var C, y: C) = x.i += y.i
+
+  var c = C(i: 1)
+  when nimvm: #XXX: This would output 2,2 in the VM, which is wrong
+    discard
+  else:
+    say c, (c += C(i: 1); c) #1,2
+
+  proc sayVar(a: var int, b: int) =
+    echo a,",",b
+
+  var d = 1
+  sayVar d, (d += 1; d) #2,2
+
+  var e = 1
+  say (addr e)[], (e += 1; e) #1,2
+
+  var f = 1
+  say f, if false: f
+         else: f += 1; f #1,2
+
+  var g = 1
+  say g + 1, if false: g
+             else: g += 1; g #2,2
+
+  proc `+=+`(x: var int, y: int): int = (inc(x, y); x)
+
+  var h = 1
+  say h, h +=+ 1 # 1,2
+
+test
+
+static:
+  test