Swift SIL: add some APIs to Location

* `var description`
* `func ==`
* `func hasSameSourceLocation(as:)`

SwiftCompilerSources/Sources/SIL/Location.swift

@@ -12,11 +12,24 @@
 
 import SILBridging
 
-public struct Location {
+public struct Location: Equatable, CustomStringConvertible {
   let bridged: swift.SILDebugLocation
-  
+
+  public var description: String {
+    let stdString = SILLocation_debugDescription(bridged)
+    return String(_cxxString: stdString)
+  }
+
   /// Keeps the debug scope but marks it as auto-generated.
   public var autoGenerated: Location {
     Location(bridged: SILLocation_getAutogeneratedLocation(bridged))
   }
+
+  public static func ==(lhs: Location, rhs: Location) -> Bool {
+    SILLocation_equal(lhs.bridged, rhs.bridged)
+  }
+
+  public func hasSameSourceLocation(as other: Location) -> Bool {
+    SILLocation_hasSameSourceLocation(bridged, other.bridged)
+  }
 }