Fix the interpretation of a 0 st_name.

The ELF spec is very clear:

-----------------------------------------------------------------------------
If the value is non-zero, it represents a string table index that gives the
symbol name. Otherwise, the symbol table entry has no name.
--------------------------------------------------------------------------

In particular, a st_name of 0 most certainly doesn't mean that the symbol has
the same name as the section.

llvm-svn: 238899
diff --git a/llvm/test/MC/ELF/weakref.s b/llvm/test/MC/ELF/weakref.s
index d263af3..76e420a 100644
--- a/llvm/test/MC/ELF/weakref.s
+++ b/llvm/test/MC/ELF/weakref.s
@@ -116,7 +116,7 @@
 // CHECK-NEXT:     Section: .text
 // CHECK-NEXT:   }
 // CHECK-NEXT:   Symbol {
-// CHECK-NEXT:     Name: .text
+// CHECK-NEXT:     Name: (0)
 // CHECK-NEXT:     Value: 0x0
 // CHECK-NEXT:     Size: 0
 // CHECK-NEXT:     Binding: Local
@@ -125,7 +125,7 @@
 // CHECK-NEXT:     Section: .text
 // CHECK-NEXT:   }
 // CHECK-NEXT:   Symbol {
-// CHECK-NEXT:     Name: .data
+// CHECK-NEXT:     Name: (0)
 // CHECK-NEXT:     Value: 0x0
 // CHECK-NEXT:     Size: 0
 // CHECK-NEXT:     Binding: Local
@@ -134,7 +134,7 @@
 // CHECK-NEXT:     Section: .data
 // CHECK-NEXT:   }
 // CHECK-NEXT:   Symbol {
-// CHECK-NEXT:     Name: .bss
+// CHECK-NEXT:     Name: (0)
 // CHECK-NEXT:     Value: 0x0
 // CHECK-NEXT:     Size: 0
 // CHECK-NEXT:     Binding: Local