[JITLink][AArch32] Fix MSVC error on missing constexpr capture

The Windows MSVC builder complains: 'ImmMask' cannot be implicitly captured because no default capture mode has been
specified
When adding the explicit capture, Clang warns: Lambda capture 'ImmMask' is not required to be captured for this use

This seems to be a known implementation divergence. Using a default value capture should avoid the issue.

llvm/unittests/ExecutionEngine/JITLink/AArch32Tests.cpp

@@ -183,7 +183,7 @@ TEST(AArch32_Relocations, Arm_Call_Bare) {
       0xffffffff, // ones
   };
 
-  auto EncodeDecode = [](int64_t In, MutableWord &Mem) {
+  auto EncodeDecode = [=](int64_t In, MutableWord &Mem) {
     Mem.patch(encodeImmBA1BlA1BlxA2(In), ImmMask);
     return decodeImmBA1BlA1BlxA2(Mem.Wd);
   };