cranelift: Remove of/nof overflow flags from icmp (#4879)

* cranelift: Remove of/nof overflow flags from icmp

Neither Wasmtime nor cg-clif use these flags under any circumstances.
From discussion on #3060 I see it's long been unclear what purpose these
flags served.

Fixes #3060, fixes #4406, and fixes #4875... by deleting all the code
that could have been buggy.

This changes the cranelift-fuzzgen input format by removing some IntCC
options, so I've gone ahead and enabled I128 icmp tests at the same
time. Since only the of/nof cases were failing before, I expect these to
work.

* Restore trapif tests

It's still useful to validate that iadd_ifcout's iflags result can be
forwarded correctly to trapif, and for that purpose it doesn't really
matter what condition code is checked.

cranelift/codegen/src/ir/condcodes.rs

@@ -55,10 +55,6 @@ pub enum IntCC {
     UnsignedGreaterThan,
     /// Unsigned `<=`.
     UnsignedLessThanOrEqual,
-    /// Signed Overflow.
-    Overflow,
-    /// Signed No Overflow.
-    NotOverflow,
 }
 
 impl CondCode for IntCC {
@@ -75,8 +71,6 @@ impl CondCode for IntCC {
             UnsignedGreaterThanOrEqual => UnsignedLessThan,
             UnsignedGreaterThan => UnsignedLessThanOrEqual,
             UnsignedLessThanOrEqual => UnsignedGreaterThan,
-            Overflow => NotOverflow,
-            NotOverflow => Overflow,
         }
     }
 
@@ -93,8 +87,6 @@ impl CondCode for IntCC {
             UnsignedGreaterThanOrEqual => UnsignedLessThanOrEqual,
             UnsignedLessThan => UnsignedGreaterThan,
             UnsignedLessThanOrEqual => UnsignedGreaterThanOrEqual,
-            Overflow => Overflow,
-            NotOverflow => NotOverflow,
         }
     }
 }
@@ -113,8 +105,6 @@ impl IntCC {
             IntCC::UnsignedGreaterThanOrEqual,
             IntCC::UnsignedGreaterThan,
             IntCC::UnsignedLessThanOrEqual,
-            IntCC::Overflow,
-            IntCC::NotOverflow,
         ]
     }
 
@@ -158,8 +148,6 @@ impl IntCC {
             UnsignedGreaterThanOrEqual => "uge",
             UnsignedLessThan => "ult",
             UnsignedLessThanOrEqual => "ule",
-            Overflow => "of",
-            NotOverflow => "nof",
         }
     }
 }
@@ -186,8 +174,6 @@ impl FromStr for IntCC {
             "ugt" => Ok(UnsignedGreaterThan),
             "ule" => Ok(UnsignedLessThanOrEqual),
             "ult" => Ok(UnsignedLessThan),
-            "of" => Ok(Overflow),
-            "nof" => Ok(NotOverflow),
             _ => Err(()),
         }
     }