[stdlib] Uninline float description (#20038)

* Uninline float description

* Uninline _floatNNToString

Author: airspeedswift

stdlib/public/core/FloatingPointTypes.swift.gyb

@@ -79,30 +79,19 @@ public struct ${Self} {
 
 extension ${Self} : CustomStringConvertible {
   /// A textual representation of the value.
-  @inlinable
   public var description: String {
-    if isFinite {
-      return _float${bits}ToString(self, debug: false)
-    } else if isNaN {
+    if isNaN {
       return "nan"
-    } else if sign == .minus {
-      return "-inf"
     } else {
-      return "inf"
+      return _float${bits}ToString(self, debug: false)
     }
   }
 }
 
 extension ${Self} : CustomDebugStringConvertible {
   /// A textual representation of the value, suitable for debugging.
   public var debugDescription: String {
-    if isFinite || isNaN {
-      return _float${bits}ToString(self, debug: true)
-    } else if sign == .minus {
-      return "-inf"
-    } else {
-      return "inf"
-    }
+    return _float${bits}ToString(self, debug: true)
   }
 }
 

stdlib/public/core/Runtime.swift.gyb

@@ -374,15 +374,13 @@ internal struct _Buffer72 {
 #if !os(Windows) && (arch(i386) || arch(x86_64))
 % end
 
-@usableFromInline // FIXME(sil-serialize-all)
 @_silgen_name("swift_float${bits}ToString")
 internal func _float${bits}ToStringImpl(
   _ buffer: UnsafeMutablePointer<UTF8.CodeUnit>,
   _ bufferLength: UInt, _ value: Float${bits},
   _ debug: Bool
 ) -> UInt
 
-@inlinable // FIXME(sil-serialize-all)
 internal func _float${bits}ToString(
   _ value: Float${bits}, debug: Bool
 ) -> String {

test/api-digester/Outputs/stability-stdlib-abi.swift.expected

@@ -14,6 +14,12 @@ Constructor _DropFirstSequence.init(_iterator:limit:dropped:) has been removed
 Constructor _PrefixSequence.init(_iterator:maxLength:taken:) has been removed
 Func _DropFirstSequence.next() has been removed
 Func _PrefixSequence.next() has been removed
+Func _float32ToString(_:debug:) has been removed
+Func _float32ToStringImpl(_:_:_:_:) has been removed
+Func _float64ToString(_:debug:) has been removed
+Func _float64ToStringImpl(_:_:_:_:) has been removed
+Func _float80ToString(_:debug:) has been removed
+Func _float80ToStringImpl(_:_:_:_:) has been removed
 Var _DropFirstSequence._dropped has been removed
 Var _DropFirstSequence._iterator has been removed
 Var _PrefixSequence._iterator has been removed