llvm-lto2: Move the LTO::run() action behind a subcommand.

Move LTO::run() to a "run" subcommand so that we can introduce new subcommands
for testing different parts of the LTO implementation.

This doesn't use llvm::cl subcommands because it doesn't appear to be currently
possible to pass an argument not associated with a subcommand to a subcommand
(e.g. -lto-use-new-pm, -mcpu=yonah).

Differential Revision: https://reviews.llvm.org/D31410

llvm-svn: 299967
diff --git a/llvm/test/ThinLTO/X86/funcimport2.ll b/llvm/test/ThinLTO/X86/funcimport2.ll
index c83370b..7338f9a 100644
--- a/llvm/test/ThinLTO/X86/funcimport2.ll
+++ b/llvm/test/ThinLTO/X86/funcimport2.ll
@@ -2,7 +2,7 @@
 ; RUN: opt -module-summary %s -o %t1.bc
 ; RUN: opt -module-summary %p/Inputs/funcimport2.ll -o %t2.bc
 
-; RUN: llvm-lto2 %t1.bc %t2.bc -o %t.o -save-temps \
+; RUN: llvm-lto2 run %t1.bc %t2.bc -o %t.o -save-temps \
 ; RUN:     -r=%t1.bc,_foo,plx \
 ; RUN:     -r=%t2.bc,_main,plx \
 ; RUN:     -r=%t2.bc,_foo,l
@@ -11,7 +11,7 @@
 
 ; We shouldn't do any importing at -O0
 ; rm -f %t.o.1.3.import.bc
-; RUN: llvm-lto2 %t1.bc %t2.bc -o %t.o -save-temps \
+; RUN: llvm-lto2 run %t1.bc %t2.bc -o %t.o -save-temps \
 ; RUN:     -O0 \
 ; RUN:     -r=%t1.bc,_foo,plx \
 ; RUN:     -r=%t2.bc,_main,plx \