Revert "[Serialization] Enable deserialization safety by default"

This reverts commit af70cc5.

# Conflicts:
#	test/Serialization/Safety/unsafe-decls.swift

Author: xymus

include/swift/Basic/LangOptions.h

@@ -366,7 +366,7 @@ namespace swift {
 
     /// Enable early skipping deserialization of decls that are marked as
     /// unsafe to read.
-    bool EnableDeserializationSafety = true;
+    bool EnableDeserializationSafety = false;
 
     /// Whether to enable the new operator decl and precedencegroup lookup
     /// behavior. This is a staging flag, and will be removed in the future.

test/Serialization/Safety/override-internal-func.swift

@@ -10,11 +10,13 @@
 // RUN:   -emit-module-interface-path %t/Lib.swiftinterface
 
 /// Build against the swiftmodule.
-// RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t
+// RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t \
+// RUN:   -enable-deserialization-safety
 
 /// Build against the swiftinterface.
 // RUN: rm %t/Lib.swiftmodule
-// RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t
+// RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t \
+// RUN:   -enable-deserialization-safety
 
 //--- Lib.swift
 

test/Serialization/Safety/skip-reading-internal-anyobject.swift

@@ -11,7 +11,8 @@
 
 /// Build client.
 // RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t \
-// RUN:   -verify -Xllvm -debug-only=Serialization 2>&1 \
+// RUN:   -verify -Xllvm -debug-only=Serialization \
+// RUN:   -enable-deserialization-safety 2>&1 \
 // RUN:   | %FileCheck --check-prefixes=SAFE %s
 
 /// Decls skips by the deserialization safety logic.

test/Serialization/Safety/skip-reading-internal-details.swift

@@ -19,7 +19,8 @@
 // RUN:   | %FileCheck --check-prefixes=NEEDED,UNSAFE %s
 
 // RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t \
-// RUN:   -verify -Xllvm -debug-only=Serialization 2>&1 \
+// RUN:   -verify -Xllvm -debug-only=Serialization \
+// RUN:   -enable-deserialization-safety 2>&1 \
 // RUN:   | %FileCheck --check-prefixes=NEEDED,CLEAN,SAFE %s
 
 /// Build against the swiftinterface.

test/Serialization/Safety/unsafe-decls.swift

@@ -4,25 +4,28 @@
 
 // RUN: %target-swift-frontend -emit-module %s \
 // RUN:   -enable-library-evolution -swift-version 5 \
+// RUN:   -enable-deserialization-safety \
 // RUN:   -Xllvm -debug-only=Serialization 2>&1 | %swift-demangle --simplified \
 // RUN:   | %FileCheck --check-prefixes=SAFETY-PRIVATE,SAFETY-INTERNAL %s
 
 // RUN: %target-swift-frontend -emit-module %s \
 // RUN:   -enable-library-evolution -swift-version 5 \
+// RUN:   -enable-deserialization-safety \
 // RUN:   -Xllvm -debug-only=Serialization \
 // RUN:   -enable-testing 2>&1 \
 // RUN:   | %FileCheck --check-prefixes=DISABLED %s
 
 /// Don't mark decls as unsafe when private import is enabled.
 // RUN: %target-swift-frontend -emit-module %s \
 // RUN:   -enable-library-evolution -swift-version 5 \
+// RUN:   -enable-deserialization-safety \
 // RUN:   -Xllvm -debug-only=Serialization \
 // RUN:   -enable-private-imports 2>&1 \
 // RUN:   | %FileCheck --check-prefixes=DISABLED %s
 
 /// Don't mark decls as unsafe without library evolution.
 // RUN: %target-swift-frontend -emit-module %s \
-// RUN:   -swift-version 5 \
+// RUN:   -enable-deserialization-safety -swift-version 5 \
 // RUN:   -Xllvm -debug-only=Serialization 2>&1 \
 // RUN:   | %FileCheck --check-prefixes=DISABLED %s
 

test/Serialization/Safety/unsafe-extensions.swift

@@ -4,25 +4,28 @@
 
 // RUN: %target-swift-frontend -emit-module %s \
 // RUN:   -enable-library-evolution -swift-version 5 \
+// RUN:   -enable-deserialization-safety \
 // RUN:   -Xllvm -debug-only=Serialization 2>&1 \
 // RUN:   | %FileCheck --check-prefixes=SAFETY-PRIVATE,SAFETY-INTERNAL %s
 
 // RUN: %target-swift-frontend -emit-module %s \
 // RUN:   -enable-library-evolution -swift-version 5 \
+// RUN:   -enable-deserialization-safety \
 // RUN:   -Xllvm -debug-only=Serialization \
 // RUN:   -enable-testing 2>&1 \
 // RUN:   | %FileCheck --check-prefixes=DISABLED %s
 
 /// Don't mark decls as unsafe when private import is enabled.
 // RUN: %target-swift-frontend -emit-module %s \
 // RUN:   -enable-library-evolution -swift-version 5 \
+// RUN:   -enable-deserialization-safety \
 // RUN:   -Xllvm -debug-only=Serialization \
 // RUN:   -enable-private-imports 2>&1 \
 // RUN:   | %FileCheck --check-prefixes=DISABLED %s
 
 /// Don't mark decls as unsafe without library evolution.
 // RUN: %target-swift-frontend -emit-module %s \
-// RUN:   -swift-version 5 \
+// RUN:   -enable-deserialization-safety -swift-version 5 \
 // RUN:   -Xllvm -debug-only=Serialization 2>&1 \
 // RUN:   | %FileCheck --check-prefixes=DISABLED %s