[lldb] [testsuite] Fix TestFixIts.py on Linux

Since D77214 there is a testsuite regression for TestFixIts.py
on Fedora 31 x86_64.
    File "/home/jkratoch/redhat/llvm-monorepo/lldb/test/API/commands/expression/fixits/TestFixIts.py", line 148, in test_with_target
      self.assertEquals(value.GetError().GetCString(), "error: No value")
  AssertionError: 'error: error: Multiple internal symbols found for \'d\'\nid = {0x00000d2a}, ran [truncated]... != 'error: No value'

That is because Fedora glibc incl. libm.so contains also ELF debug
symbols and there exists a 'd' symbol:
  (gdb) p d
  $1 = {i = {0, 1076887552}, d = 16}
  (gdb) p &d
  $2 = (const number *) 0x7ffff78e8bc0 <d>
  (gdb) info sym 0x7ffff78e8bc0
  d in section .rodata of /lib64/libm.so.6

  $ nm /lib64/libm.so.6 |grep ' d$'
  00000000000bfbc0 r d
  00000000000caa20 r d
  00000000000caa20 r d
  00000000000caa20 r d

  glibc-build$ for i in `find -name "*.o"`;do nm 2>/dev/null $i|grep ' d$' && echo $i;done
  0000000000000080 r d
  ./math/s_atan-fma4.o
  0000000000000080 r d
  ./math/s_atan-avx.o
  0000000000000080 r d
  ./math/s_atan.o

lldb/test/API/commands/expression/fixits/TestFixIts.py

@@ -107,11 +107,11 @@ class ExprCommandWithFixits(TestBase):
         struct S1 : public T {
           using T::TypeDef;
           int f() {
-            Data d;
-            d.m = 123;
+            Data data;
+            data.m = 123;
             // The first error as the using above requires a 'typename '.
             // Will trigger a Fix-It that puts 'typename' in the right place.
-            typename S1<T>::TypeDef i = &d;
+            typename S1<T>::TypeDef i = &data;
             // i has the type "Data *", so this should be i.m.
             // The second run will change the . to -> via the Fix-It.
             return i.m;