Add -disable-sil-linking to four simple SIL serialization tests. (#9723)

What these tests are testing has nothing to do with whether or not we
deserialize anything from the standard library, and not doing so saves
more than two minutes (single-threaded) on my machine from each test.

Author: jrose-apple

test/Serialization/alignment.swift

@@ -1,7 +1,7 @@
 // RUN: rm -rf %t
 // RUN: mkdir -p %t
 // RUN: %target-swift-frontend %s -emit-module -parse-as-library -o %t
-// RUN: %target-sil-opt -enable-sil-verify-all %t/alignment.swiftmodule -o - | %FileCheck %s
+// RUN: %target-sil-opt -disable-sil-linking -enable-sil-verify-all %t/alignment.swiftmodule -o - | %FileCheck %s
 
 //CHECK: @_alignment(16) struct Foo {
 @_alignment(16) struct Foo {}

test/Serialization/default-witness-table-deserialization.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend %s -module-name Test -sil-serialize-all -emit-module -emit-module-path - -o /dev/null | %target-sil-opt -enable-sil-verify-all -module-name="Test" | %FileCheck %s
+// RUN: %target-swift-frontend %s -module-name Test -sil-serialize-all -emit-module -emit-module-path - -o /dev/null | %target-sil-opt -enable-sil-verify-all -disable-sil-linking -module-name="Test" | %FileCheck %s
 
 // Check that default witness tables are properly deserialized.
 // rdar://problem/29173229

test/Serialization/global_init.swift

@@ -2,7 +2,7 @@
 // RUN: mkdir -p %t
 // RUN: %target-swift-frontend -emit-module -parse-as-library -sil-serialize-all -o %t %s
 // RUN: llvm-bcanalyzer %t/global_init.swiftmodule | %FileCheck %s -check-prefix=BCANALYZER
-// RUN: %target-sil-opt -enable-sil-verify-all %t/global_init.swiftmodule | %FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all -disable-sil-linking %t/global_init.swiftmodule | %FileCheck %s
 
 // BCANALYZER-NOT: UnknownCode
 

test/Serialization/serialize_attr.swift

@@ -2,7 +2,7 @@
 // RUN: mkdir -p %t
 // RUN: %target-swift-frontend -emit-module -parse-as-library -sil-serialize-all -o %t %s
 // RUN: llvm-bcanalyzer %t/serialize_attr.swiftmodule | %FileCheck %s -check-prefix=BCANALYZER
-// RUN: %target-sil-opt -enable-sil-verify-all %t/serialize_attr.swiftmodule | %FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all -disable-sil-linking %t/serialize_attr.swiftmodule | %FileCheck %s
 
 // BCANALYZER-NOT: UnknownCode