[ORC] Rename VSO to JITDylib.

VSO was a little close to VDSO (an acronym on Linux for Virtual Dynamic Shared
Object) for comfort. It also risks giving the impression that instances of this
class could be shared between ExecutionSessions, which they can not.

JITDylib seems moderately less confusing, while still hinting at how this
class is intended to be used, i.e. as a JIT-compiled stand-in for a dynamic
library (code that would have been a dynamic library if you had wanted to
compile it ahead of time).

llvm-svn: 340084
diff --git a/llvm/unittests/ExecutionEngine/Orc/OrcTestCommon.h b/llvm/unittests/ExecutionEngine/Orc/OrcTestCommon.h
index c6caaf0..05a0b11 100644
--- a/llvm/unittests/ExecutionEngine/Orc/OrcTestCommon.h
+++ b/llvm/unittests/ExecutionEngine/Orc/OrcTestCommon.h
@@ -44,12 +44,12 @@
 // (4) FooSym, BarSym, BazSym, QuxSym -- JITEvaluatedSymbols with FooAddr,
 //     BarAddr, BazAddr, and QuxAddr respectively. All with default strong,
 //     linkage and non-hidden visibility.
-// (5) V -- A VSO associated with ES.
+// (5) V -- A JITDylib associated with ES.
 class CoreAPIsBasedStandardTest : public testing::Test {
 public:
 protected:
   ExecutionSession ES;
-  VSO &V = ES.createVSO("V");
+  JITDylib &JD = ES.createJITDylib("JD");
   SymbolStringPtr Foo = ES.getSymbolStringPool().intern("foo");
   SymbolStringPtr Bar = ES.getSymbolStringPool().intern("bar");
   SymbolStringPtr Baz = ES.getSymbolStringPool().intern("baz");