Add generator requirements to cxx interop tests

The constructors-copy-irgen and constructors-irgen tests check code
generated by the X86 and ARM backends and will fail spectacularly if we
don't have the backend enabled. Adding the necessary codegenerator
requirements to those tests.

Author: etcwilde

test/Interop/Cxx/class/constructors-copy-irgen.swift

@@ -4,6 +4,9 @@
 // RUN: %swift -module-name Swift -target armv7-none-linux-androideabi -dump-clang-diagnostics -I %S/Inputs -enable-experimental-cxx-interop -emit-ir %s -parse-stdlib -parse-as-library -disable-legacy-type-info | %FileCheck %s -check-prefix=ITANIUM_ARM
 // RUN: %swift -module-name Swift -target x86_64-unknown-windows-msvc -dump-clang-diagnostics -I %S/Inputs -enable-experimental-cxx-interop -emit-ir %s -parse-stdlib -parse-as-library -disable-legacy-type-info | %FileCheck %s -check-prefix=MICROSOFT_X64
 
+// REQUIRES: CODEGENERATOR=X86
+// REQUIRES: CODEGENERATOR=ARM
+
 import Constructors
 import TypeClassification
 

test/Interop/Cxx/class/constructors-irgen.swift

@@ -4,6 +4,9 @@
 // RUN: %swift -module-name Swift -target armv7-unknown-linux-androideabi -dump-clang-diagnostics -I %S/Inputs -enable-experimental-cxx-interop -emit-ir %s -parse-stdlib -parse-as-library -disable-legacy-type-info | %FileCheck %s -check-prefix=ITANIUM_ARM
 // RUN: %swift -module-name Swift -target x86_64-unknown-windows-msvc -dump-clang-diagnostics -I %S/Inputs -enable-experimental-cxx-interop -emit-ir %s -parse-stdlib -parse-as-library -disable-legacy-type-info | %FileCheck %s -check-prefix=MICROSOFT_X64
 
+// REQUIRES: CODEGENERATOR=X86
+// REQUIRES: CODEGENERATOR=ARM
+
 import Constructors
 import TypeClassification