RFR: JDK-8155641: Correct merge typo in compare script

[Erik Joelsson]

An apparent typo has appeared in common/autoconf/compare.sh.in which I 
think originates from a merge changeset. It prevents clean comparisons 
from being done so I would like to have it fixed asap.

Bug: https://bugs.openjdk.java.net/browse/JDK-8155641
Patch:
diff -r d8b1e1832b0e common/autoconf/compare.sh.in
--- a/common/autoconf/compare.sh.in
+++ b/common/autoconf/compare.sh.in
@@ -31,7 +31,7 @@

  export LEGACY_BUILD_DIR=@OPENJDK_TARGET_OS at -@OPENJDK_TARGET_CPU_LEGACY@

-sexport OPENJDK_TARGET_OS="@OPENJDK_TARGET_OS@"
+export OPENJDK_TARGET_OS="@OPENJDK_TARGET_OS@"
  export OPENJDK_TARGET_CPU="@OPENJDK_TARGET_CPU@"
  export OPENJDK_TARGET_CPU_LIBDIR="@OPENJDK_TARGET_CPU_LIBDIR@"
  export DEBUG_LEVEL="@DEBUG_LEVEL@"


/Erik