COFF: Fix short import lib import name type bitshift

As per the PE COFF spec (section 8.3, Import Name Type)
Offset: 18 Size 2 bits Name: Type
Offset: 20 Size 3 bits Name: Name Type

Offset: 20 added based on 18+2

Partially commited as rL279069

Differential Revision: https://reviews.llvm.org/D23540

llvm-svn: 283055
diff --git a/llvm/test/tools/llvm-readobj/coff-exports-implib.test b/llvm/test/tools/llvm-readobj/coff-exports-implib.test
index 9715109..2b32738 100644
--- a/llvm/test/tools/llvm-readobj/coff-exports-implib.test
+++ b/llvm/test/tools/llvm-readobj/coff-exports-implib.test
@@ -3,20 +3,24 @@
 CHECK: File: library.dll
 CHECK: Format: COFF-import-file
 CHECK: Type: const
+CHECK: Name type: undecorate
 CHECK: Symbol: __imp__constant
 
 CHECK: File: library.dll
 CHECK: Format: COFF-import-file
 CHECK: Type: data
+CHECK: Name type: noprefix
 CHECK: Symbol: __imp__data
 
 CHECK: File: library.dll
 CHECK: Format: COFF-import-file
 CHECK: Type: code
+CHECK: Name type: name
 CHECK: Symbol: __imp__function
 
 CHECK: File: library.dll
 CHECK: Format: COFF-import-file
 CHECK: Type: code
+CHECK: Name type: ordinal
 CHECK: Symbol: __imp__ordinal