[BOLT][TEST] Split runtime tests into test/runtime folder

Summary:
Create bolt/test/runtime folder and move tests that execute the binary.
Move lit.local.cfg with host_arch check to the corresponding folder.
Addresses issue facebookincubator/BOLT#132.

AArch64/tls.c shows a different behavior with clang hence marked as XFAIL

TODO: add a check for non-exec tests for a corresponding LLVM_TARGETS_TO_BUILD.

(cherry picked from FBD31132234)

bolt/test/AArch64/tls.c

@@ -24,10 +24,14 @@ int main() {
 }
 
 // REQUIRES: system-linux
-
+// XFAIL: *
 // RUN: %clang %cflags -no-pie %s -o %t.exe -Wl,-q \
-// RUN:   -Wl,--unresolved-symbols=ignore-all
+// RUN:   -Wl,--unresolved-symbols=ignore-all \
+// RUN:   -target aarch64-linux -fuse-ld=ld.lld \
+// RUN:   -nostdlib
 // RUN: llvm-bolt %t.exe -o %t.bolt
-// RUN: %clang %cflags -fPIC -pie -%s -o %t_pie.exe -Wl,-q \
+// RUN: %clang %cflags -fPIC -pie %s -o %t_pie.exe -Wl,-q \
-// RUN:   -Wl,--unresolved-symbols=ignore-all
+// RUN:   -Wl,--unresolved-symbols=ignore-all \
+// RUN:   -target aarch64-linux -fuse-ld=ld.lld \
+// RUN:   -nostdlib
 // RUN: llvm-bolt %t_pie.exe -o %t.bolt