Disable concurrent osr.

R=jarin@chromium.org
BUG=v8:4650
LOG=Y

Review URL: https://codereview.chromium.org/1574113009

Cr-Commit-Position: refs/heads/master@{#33261}

src/flag-definitions.h

@@ -407,7 +407,7 @@ DEFINE_INT(concurrent_recompilation_delay, 0,
            "artificial compilation delay in ms")
 DEFINE_BOOL(block_concurrent_recompilation, false,
             "block queued jobs until released")
-DEFINE_BOOL(concurrent_osr, true, "concurrent on-stack replacement")
+DEFINE_BOOL(concurrent_osr, false, "concurrent on-stack replacement")
 DEFINE_IMPLICATION(concurrent_osr, concurrent_recompilation)
 
 DEFINE_BOOL(omit_map_checks_for_leaf_maps, true,