Rename ScriptParser.{cpp,h} -> ScriptLexer.{cpp,h}.

These files contain a lexer, so the new names are better.
The parser is in LinkerScript.{cpp,h}.

llvm-svn: 295022
diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index a0b8530..1405fa5 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -17,7 +17,7 @@
 #include "InputSection.h"
 #include "Memory.h"
 #include "OutputSections.h"
-#include "ScriptParser.h"
+#include "ScriptLexer.h"
 #include "Strings.h"
 #include "SymbolTable.h"
 #include "Symbols.h"
@@ -1016,12 +1016,12 @@
   return 0;
 }
 
-class elf::ScriptParser final : public ScriptParserBase {
+class elf::ScriptParser final : public ScriptLexer {
   typedef void (ScriptParser::*Handler)();
 
 public:
   ScriptParser(MemoryBufferRef MB)
-      : ScriptParserBase(MB),
+      : ScriptLexer(MB),
         IsUnderSysroot(isUnderSysroot(MB.getBufferIdentifier())) {}
 
   void readLinkerScript();