[lldb][test] Make hex prefix optional in DWARF union types test

Fixes llvm#159401

On Windows there is no hex prefix, I suspect because somewhere we
print a pointer. I'd prefer to fix that itself but can't get to
a Windows machine at the moment. It's not important to the purpose
of the test anyway.

Author: DavidSpickett

lldb/test/Shell/SymbolFile/DWARF/union-types-no-member-location.yaml

@@ -52,7 +52,7 @@
 # RUN: cat %t.stderr | FileCheck --allow-empty --check-prefix=STDERR %s
 
 # STDOUT: Found 1 types:
-# STDOUT: 0x{{[0-9a-fA-F]+}}: Type{0x0000002b} , name = "UnionType", size = 32, compiler_type = 0x{{[0-9a-fA-F]+}} union UnionType {
+# STDOUT: {{(0x)?[0-9a-fA-F]+}}: Type{0x0000002b} , name = "UnionType", size = 32, compiler_type = 0x{{[0-9a-fA-F]+}} union UnionType {
 
 # STDERR-NOT: error: union-types-no-member-location.yaml.tmp 0x00000031: DW_TAG_member 'array' refers to type 0x000000000000001f which extends beyond the bounds of 0x0000002b